Washington’s FL Modify 631 is the petition packet a parent files in Superior Court to ask a judge to change an existing Parenting Plan, Residential Schedule, or custody order, and it is part of the state’s “FL Modify” family of modification forms governed by Chapter 26.09 RCW. You file it when life has changed enough that the current parenting order no longer fits your child’s needs, and the form tells the court exactly what you want changed and why.
Getting this form right matters because Washington does not let parents change a parenting plan on a whim. Judges first decide whether you cleared a legal bar called adequate cause, and a poorly written petition can be tossed out before a judge ever looks at the merits. According to the Washington Courts forms portal, the parenting-plan modification forms are among the most-used family law filings in the state, and self-represented parents make up a large share of these filers.
In this guide, you will learn:
- 📝 What FL Modify 631 does and who must file it under RCW 26.09.260
- 📂 Every document and number to gather before you open the form
- 🖊️ A line-by-line walkthrough of each box, with sample entries you can copy
- 👨👩👧 Three full real-world examples that follow named parents from start to finish
- ⚖️ The filing fees, deadlines, and mistakes that get petitions rejected
What the Form Is and Who Must File It
FL Modify 631 is a Petition to Change a Parenting Plan, Residential Schedule, or Custody Order. It sits inside the broader “FL Modify” group on the Washington Courts website, which also includes the matching Summons (FL Modify 600), the Response (FL Modify 602), and the final order (FL Modify 610). The petition is the document that actually asks the court to act, so it is the heart of the whole packet.
You must file this petition if you are a parent, or a person who already holds a custody order, and you want the court to change the parenting terms in a final order. The legal authority for this comes from RCW 26.09.260, which is the statute that controls when and how a Washington court may modify a parenting plan. That statute is strict on purpose, because children do better with stable, predictable schedules.
The form solves a real problem: your final parenting plan was built around facts that may no longer be true. A parent may have moved, lost a job, developed a health issue, or the child’s needs may have shifted as they grew. If you ignore the form and simply stop following the order, you can be held in contempt under RCW 26.09.160, which carries fines and even jail in serious cases.
A common misconception is that both parents must agree before you can file. That is false. One parent can file alone, and the other parent then gets a chance to respond, though an agreed change is faster and cheaper than a contested one.
Before You Start: Documents and Information You Need
Gather everything below before you open the form, because missing items are the top reason filings stall at the clerk’s window. Having each piece ready also helps you write a stronger, more specific petition.
- A certified copy of your current Parenting Plan or custody order. You need the exact wording and the date the judge signed it, because you must attach it and describe what you want changed. Without it, the clerk may refuse your packet.
- Your court case number. Every modification is filed in the same county and under the same case number as the original order, so pulling the wrong number sends your papers to the wrong file.
- Full legal names and birthdates of each child. The court matches children to the existing order, and a wrong birthdate can delay processing.
- Both parents’ current addresses. You need the other parent’s address to serve them, and service cannot happen without it.
- A written timeline of the changes since the last order. Judges decide adequate cause on facts, so dates and events are your evidence.
- Your proposed new Parenting Plan (FL All Family 140). You must show the court the schedule you want, not just say the old one is broken.
- The Confidential Information form (FL All Family 001). Washington requires this to keep private data, like Social Security numbers, out of the public file.
- The filing fee or a fee waiver request (GR 34). No fee and no waiver means no filing.
- Any evidence of harm or major change. Police reports, medical records, or school records support the reasons you list in the petition.
If you are missing a certified copy of the original order, request one from the Superior Court Clerk in the county where it was entered before you do anything else. A plain printout from an online docket is usually not enough for the court file.
Where to Get the Form and How to Access It
You can download FL Modify 631 and its companion forms free from the Washington Courts forms library, which lists every state-approved family law form by number and revision date. Always check the revision date printed in the bottom corner of the form, and use the most current version, because courts reject outdated forms. As of this writing, the parenting-plan modification forms carry recent revision dates, so confirm yours before filing.
You can fill the form out in three ways. You can type directly into the fillable PDF on your computer, you can use the guided interview at Washington Forms Online, or you can print it and write by hand in black ink. Typing is best because handwriting errors and unreadable text cause clerks and judges to misread your requests.
Many counties also sell a complete modification “packet” through the Superior Court Clerk that bundles the state forms with any local forms your county requires. For example, Skagit County and other counties add local cover sheets, so check your county’s clerk page before you assume the state forms alone are enough.
A misconception is that you can file the federal-style or another state’s parenting forms in Washington. You cannot. Washington courts only accept Washington forms, and your case must be filed in the Washington county that entered or has jurisdiction over the original order.
Step-by-Step: How to Fill Out FL Modify 631 Line by Line
Work through the form in the order the fields appear. Use the exact box labels printed on the form, write sample entries in italics the way they would look on paper, and never leave a required field blank, since blanks read as “no answer” to the court.
Caption: County, Court, and Case Number
The top block of the form, the caption, asks for the Superior Court county, the petitioner’s and respondent’s names, and the case number. In plain English, this is the header that tells the court which case this petition belongs to. Fill it in by copying the county and case number exactly from your existing order, and list the parents’ names in the same order as the original case.
For example, Maria Lopez writes King County Superior Court, lists herself as petitioner, David Lopez as respondent, and copies case number 21-3-04567-8 SEA. If your original order is from another county, you generally must file in that same county, so do not switch venues on your own.
A common mistake is reversing the petitioner and respondent names from the original case, which confuses the file and can route your petition to the wrong judge. People also wrongly believe a new case number is assigned, but a modification keeps the original number.
Part 1: Who Is Asking for the Change (Petitioner)
This section asks who is filing the petition. In plain English, it identifies you as the parent requesting the change. Enter your full legal name as it appears on the existing order, and check the box that describes your role, such as a parent.
For example, David Lopez writes his name and checks the box marking him as the father and a parent under the current plan. If you have changed your name since the last order, use your current legal name but note the prior name so the court can match you to the file.
A frequent error is using a nickname or shortened name, which breaks the match to the original order. Some filers think only mothers or only “primary” parents can file, but either parent named in the order may file.
Part 2: The Children This Petition Is About
This part asks for each child covered by the order. In plain English, it lists the kids whose schedule you want to change. Enter each child’s full legal name, birthdate in MM/DD/YYYY format, and current age.
For example, Maria Lopez enters Sofia Lopez, 03/14/2015, age 11 and Mateo Lopez, 08/02/2018, age 7. If a child has turned 18 since the order, you usually cannot modify the plan for that child, because the court loses authority over an adult.
A common mistake is listing children who are not part of the original order, which the court will strike. People also wrongly assume they can add a child from a different relationship here, but each case covers only its own children.
Part 3: The Order You Want to Change
This section asks which existing order you are modifying and when it was signed. In plain English, it points the judge to the exact document you want changed. Enter the type of order and the date the judge signed it.
For example, David Lopez writes Final Parenting Plan signed 06/10/2021. Attach a certified copy so the judge can compare the old terms to your request, because a judge will not modify an order they cannot see.
A frequent error is guessing the signing date, which makes your petition look unreliable. Some filers think a temporary order counts here, but you modify the final order, not a temporary one.
Part 4: Type of Modification (Major or Minor)
This is the most important section, because it tells the court whether you seek a major change or a minor adjustment. In plain English, a major change shifts where the child mainly lives, while a minor change tweaks the schedule without moving the child’s main home. Check the box that fits your request, and read it carefully.
For example, Aisha Bell checks the minor modification box because she only wants to shift weekend exchanges by a few hours, not change the child’s home base. The line you choose decides which legal test under RCW 26.09.260 applies, and a major change faces a much higher bar.
A common and costly mistake is checking “minor” to seem less threatening when you really want a major change, which leads a judge to deny the relief you actually need. Many people wrongly believe any schedule change is “minor,” but moving the primary home is always treated as major.
Part 5: Reasons for the Change (Adequate Cause / Substantial Change)
This section asks you to explain why the change is needed. In plain English, you must show a substantial change in circumstances of the child or the nonmoving parent that was not known when the last order was entered. Write specific facts with dates, not opinions.
For example, Janet Cole writes, “On 02/2026 the father relocated 200 miles away, ending his ability to follow the midweek schedule.” The court uses these facts to decide adequate cause, the gatekeeping test that must be met before a full hearing, so vague statements like “he is a bad parent” will not survive.
A frequent mistake is listing reasons that existed before the last order, which the law bars as a basis for change. People often believe a parent’s new relationship alone is enough, but courts require an effect on the child, not just a lifestyle change.
Part 6: What You Want the Court to Order
This part asks for the specific outcome you want. In plain English, tell the judge exactly what the new plan should say. Be concrete about days, times, and who has decision-making power.
For example, Maria Lopez writes that she wants the children to live with her on school nights and the father to have alternate weekends and half of summer. Attach your proposed Parenting Plan, FL All Family 140, so the court can see the schedule in full.
A common mistake is asking for something vague like “more time,” which a judge cannot enter as an order. Some filers think the court will write the schedule for them, but you must propose it.
Part 7: Other Court Cases and Protection Orders
This section asks about related cases, such as protection orders or child support cases. In plain English, it makes sure the court knows about anything that affects the children’s safety or support. Check the boxes that apply and list case numbers.
For example, Aisha Bell checks “yes” and lists a no-contact order against the other parent with its case number. If there is domestic violence, this section matters under RCW 26.09.191, which limits a violent parent’s time and decision-making.
A frequent error is hiding a protection order, which can be discovered and damage your credibility. People wrongly assume support cases are unrelated, but the court often coordinates them.
Part 8: Signature and Verification
The final section is where you sign under penalty of perjury. In plain English, your signature swears that everything in the petition is true. Sign, date, print your name, and add your phone and address.
For example, David Lopez signs, dates it 05/29/2026, and prints his name and contact details. Under CR 4.1 and Washington perjury law, a false statement here is a crime, so reread every fact before you sign.
A common mistake is signing before filling in the date or contact lines, which leaves the court unable to reach you. Some people believe a typed name counts as a signature on a paper filing, but most courts require a handwritten or valid electronic signature.
Three Filled-Out Examples Using Real Scenarios
Below are three of the most common situations, each following one parent through the petition. Use them as models for tone and detail, not as legal advice for your exact case.
Scenario 1: Maria Lopez — Major change after the other parent’s relocation
| Form Section | What Maria Enters |
|---|---|
| Caption | King County Superior Court, Case 21-3-04567-8 SEA |
| Petitioner (Part 1) | Maria Lopez, mother and parent |
| Children (Part 2) | Sofia Lopez 03/14/2015; Mateo Lopez 08/02/2018 |
| Order to change (Part 3) | Final Parenting Plan signed 06/10/2021 |
| Type (Part 4) | Major modification checked |
| Reasons (Part 5) | Father moved 200 miles away in 02/2026, breaking the weekday schedule |
| What she wants (Part 6) | Children live with her on school nights; father gets alternate weekends |
| Signature (Part 8) | Signed and dated 05/29/2026 |
Scenario 2: Aisha Bell — Minor adjustment to exchange times
| Form Section | What Aisha Enters |
|---|---|
| Caption | Pierce County Superior Court, Case 22-3-01122-3 |
| Petitioner (Part 1) | Aisha Bell, mother and parent |
| Children (Part 2) | Noah Bell 11/09/2017 |
| Order to change (Part 3) | Final Parenting Plan signed 09/01/2022 |
| Type (Part 4) | Minor modification checked |
| Reasons (Part 5) | Child’s new school start time makes 7 a.m. exchange unworkable |
| What she wants (Part 6) | Move weekday exchange from 7:00 a.m. to 8:30 a.m. |
| Other cases (Part 7) | Lists existing no-contact order and case number |
Scenario 3: Janet Cole — Agreed modification both parents support
| Form Section | What Janet Enters |
|---|---|
| Caption | Snohomish County Superior Court, Case 19-3-07788-1 |
| Petitioner (Part 1) | Janet Cole, mother and parent |
| Children (Part 2) | Liam Cole 05/22/2012; Ava Cole 01/30/2014 |
| Order to change (Part 3) | Final Parenting Plan signed 03/15/2019 |
| Type (Part 4) | Minor modification, marked as agreed |
| Reasons (Part 5) | Both parents agree to a 50/50 summer schedule as the kids are older |
| What she wants (Part 6) | Equal alternating-week summer residential time |
| Signature (Part 8) | Both parents sign the agreed paperwork |
How to File the Completed Form
Once your petition, proposed parenting plan, summons, and confidential information form are complete, you file them with the Superior Court Clerk in the correct county. Keep copies of everything, because you must serve the other parent and keep proof.
- In person. Take the originals and copies to the Superior Court Clerk’s counter in your county courthouse. The clerk stamps your copy, which is your proof of filing. Bring payment for the filing fee.
- By mail. Mail the signed originals and copies to the clerk’s mailing address listed on your county Superior Court page, with the fee or a GR 34 fee waiver request. Use tracked mail and keep the receipt as proof.
- Electronically. Many counties accept e-filing through their portals, such as the King County or Pierce County e-filing systems, where you upload PDFs and pay by card. Save the confirmation email as your proof of filing.
Filing fees vary by county and by whether the original order is from the same county. A minor adjustment motion may carry a small fee, while opening a new modification action can run a few hundred dollars, so confirm the current amount with your clerk. Accepted payment is usually cash, card, or check, depending on the channel.
After filing, you must serve the other parent with the summons and petition, normally by personal service from someone over 18 who is not you. Then file proof of service, such as FL All Family 101, so the court knows the other side received notice.
What Happens After You File
After filing and serving, the court first decides adequate cause, the threshold test under RCW 26.09.270. A judge or commissioner reviews your stated facts, often at a short hearing, to decide whether your case is strong enough to move forward.
If the court finds adequate cause, your case proceeds toward a full hearing or trial where both parents present evidence. If the court finds no adequate cause, your petition is dismissed, and the existing plan stays in place. This gatekeeping step exists to protect children from repeated, weak challenges to a stable schedule.
The other parent has a set time to file a Response (FL Modify 602) after being served, generally 20 days for in-state service and 60 days if served outside Washington. If they do not respond in time, you may ask for a default order, which lets the court decide based on your papers alone.
A common misconception is that filing freezes the current plan or changes it right away. It does not. The existing order stays fully in force until a judge signs a new one, so you must keep following the current schedule.
Mistakes to Avoid When Filling Out the Form
Each field on this form is its own chance to slip up, so review this list before you file.
- Checking “minor” when you want a major change, which leads the judge to deny the relief you truly need.
- Listing reasons that existed before the last order, which the law bars and which can sink your petition.
- Leaving the adequate-cause facts vague, which causes the court to dismiss at the gatekeeping stage.
- Using a nickname instead of your legal name, which breaks the match to the original case file.
- Copying the wrong case number, which routes your petition to the wrong file or county.
- Forgetting to attach the certified existing order, which leaves the judge unable to compare terms.
- Skipping the proposed Parenting Plan, which gives the court nothing concrete to enter.
- Filing in the wrong county, which can force you to refile and lose time.
- Signing without dating or adding contact info, which leaves the court unable to reach you.
- Failing to serve the other parent properly, which stops the case from moving at all.
- Hiding a protection order in Part 7, which damages your credibility when discovered.
- Using an outdated form version, which clerks reject at the counter.
Do’s and Don’ts
These quick rules keep your filing clean and credible.
Do:
- Do use your full legal name everywhere, because the court cross-checks it against the original order.
- Do write specific dates and facts, because adequate cause is decided on evidence, not opinion.
- Do attach a certified copy of the current order, because the judge needs to see what you want changed.
- Do propose a complete new Parenting Plan, because the court can only enter a concrete schedule.
- Do keep stamped copies and proof of service, because they prove your case is properly before the court.
- Do confirm the current fee and form version with your clerk, because both change over time.
Don’t:
- Don’t stop following the current plan, because it stays in force until a judge signs a new one.
- Don’t exaggerate or guess facts, because you sign under penalty of perjury.
- Don’t pick “minor” to seem less aggressive, because it limits what the judge can grant.
- Don’t leave required boxes blank, because blanks read as “no answer.”
- Don’t serve the papers yourself, because service must come from a neutral adult over 18.
- Don’t miss the response or hearing deadlines, because the court can rule without your input.
Pros and Cons of Filing on Your Own vs. With Help
Deciding whether to file pro se or hire help depends on how contested and complex your case is.
Pros of filing on your own:
- You save on attorney fees, which can be significant in a long custody fight.
- You control the timeline and the wording of your own petition.
- The state forms and Washington LawHelp guides are free and written for self-represented filers.
- Simple, agreed changes often move smoothly without a lawyer.
- You learn your own case deeply, which helps if you must speak in court.
Cons of filing on your own:
- You may misjudge the major-versus-minor test and lose the relief you need.
- Adequate-cause writing is technical, and weak facts get dismissed early.
- You face deadlines and service rules that are easy to miss without guidance.
- A contested case with allegations under RCW 26.09.191 can quickly outgrow a self-filer.
- Mistakes can be costly to fix and may delay relief for your child.
FAQs
Is FL Modify 631 the right form to change a final parenting plan?
Yes. It is the petition that asks a Washington court to change a final Parenting Plan, Residential Schedule, or custody order, and it is filed with the matching summons and proposed plan.
Do I file in the same county as my original order?
Yes. Modifications are filed under the original case number in the county that entered or has jurisdiction over the existing order, not in a new county of your choosing.
Do both parents have to agree before I file?
No. One parent can file alone, and the other parent then has a set time to respond, though agreed changes are faster and cheaper.
Does filing this petition change my current schedule right away?
No. The existing order stays fully in force until a judge signs a new one, so you must keep following the current plan.
Do I check “major” or “minor” in Part 4 if I want my child to live with me?
Yes, check major. Moving the child’s primary home is always treated as a major modification, which faces a higher legal test.
Do I write reasons that happened before my last order in Part 5?
No. The law bars facts known at the time of the last order, so list only changes that arose afterward.
Do I need to attach a proposed Parenting Plan?
Yes. Attach FL All Family 140 so the court can see the exact schedule you want, because a judge cannot enter a vague request.
Do I list children from another relationship in Part 2?
No. Only list the children covered by the order you are modifying, because each case covers only its own children.
Is there a filing fee for this petition?
Yes, in most cases, though amounts vary by county and case type, and you can request a GR 34 fee waiver if you cannot afford it.
Do I have to serve the other parent myself?
No. Service must come from a neutral adult over 18 who is not you, and you then file proof of service with the court.
Does the court decide my case at the first hearing?
No. The court first decides adequate cause, the gatekeeping test, and only then does a contested case move toward a full hearing or trial.
Do I use the newest version of the form?
Yes. Always download the current version from the Washington Courts site and check the revision date, because clerks reject outdated forms.
Do I report a protection order on the form?
Yes. You must disclose protection or no-contact orders in Part 7, because hiding them harms your credibility and can affect safety findings.
Related reading
- How to Fill Out Washington Form FL All Family 001 (w/Examples) + FAQs
- How to Fill Out Washington Form FL All Family 132 (w/Examples) + FAQs
- How to Fill Out Washington Form FL Parentage 301 (w/Examples) + FAQs
- How to Fill Out Washington FL Modify 504 (w/Examples) + FAQs
- How to Fill Out Washington FL Modify 521 (w/Examples) + FAQs
- How to Fill Out Washington FL Modify 601 (w/Examples) + FAQs
- How to Fill Out California Form FL-120 (w/Examples) + FAQs