How to Fill Out Form 4-11: New York Child Support Modification Petition

To fill out New York Family Court Form 4-11, you identify the parties and the existing support order, check the ground that entitles you to a modification, describe the change in specific factual terms, state exactly what you want the court to do, and sign the last page. The form is a four-page petition to modify an existing child or spousal support order, available from any Family Court clerk’s office or the New York State Unified Court System website.¹ Getting the details right is what separates a petition the court can act on from one that goes nowhere.

Confirm You Have Grounds Before You Start Writing

Section 5 of the form asks you to check the ground you’re relying on, so you need to know which one fits before you fill in anything else. New York law recognizes three.²

A substantial change in circumstances. This is the broadest ground and covers job loss, serious illness, disability, remarriage of either party, or a significant change in the child’s needs. The change must be meaningful and ongoing, not temporary.
At least three years since the current order was entered, last modified, or last adjusted. No dramatic change required.
A gross income change of 15 percent or more for either party since the order was entered or last modified. If you’re the paying parent and your income dropped, the reduction must have been involuntary, and you must show you tried to find comparable work.

The three-year and 15-percent grounds only apply to orders entered or modified on or after October 13, 2010, and don’t apply if both parties opted out of those provisions in a written agreement.¹ For older orders, or for orders where those triggers were waived, substantial change is your only path.

Incarceration is not automatically disqualifying. New York treats a prison term as a possible substantial change in circumstances as long as the incarceration didn’t result from failing to pay support or from an offense against the custodial parent or the child named in the order.²

What to Have in Front of You

Gather these before you sit down with the form. Missing information will slow the case or force a second trip to the courthouse.

The current support order or judgment, including the exact date it was entered, the issuing court, the docket or index number, and its specific terms. A true copy must be attached to the petition.¹
Personal Information Form 4-5/5-1d. This companion form collects Social Security numbers for both parties and any dependent children and is filed alongside Form 4-11.
Financial Disclosure Affidavit (Form 4-17a). You’ll bring this completed to the court date. It covers income, expenses, assets, and debts.³
Proof of the changed circumstances: pay stubs, tax returns, termination letters, medical records, documentation of a new child’s expenses, or proof of the other party’s increased income.
Arrears information. If you owe past-due support, you’ll need the amount and an explanation for why you didn’t seek modification sooner.⁴

Filling Out the Petition Section by Section

The form runs four pages. Some sections are quick. The ones that matter are the ones where the magistrate will look for facts, not conclusions.

Section 1: Party Information

Enter your full name, date of birth, and residential address. If you don’t want the respondent to know where you live, common in domestic violence situations, write “CONFIDENTIAL” on the address line and provide your actual address only on the separate information sheet.⁴ For the respondent, enter their name, date of birth, and current address. If you don’t know their current address, use the last one you had.

Section 2: The Prior Order

Fill in the date of the existing order, both parties’ names as they appeared on it, the docket or index number, and the terms it set: monthly payment, health insurance obligations, and add-on expenses like daycare or unreimbursed medical costs. If the order came from a court other than the one where you’re filing, note that court’s name and location.

Section 3: The Children

List each child covered by the order with full name and date of birth. If more than three children are involved, attach an additional sheet.

Section 5: Grounds

Check the box matching the ground you confirmed earlier and fill in the supporting detail. Specificity is the whole point here. “My income decreased” gives the magistrate nothing. “I was laid off from my position as a warehouse supervisor in March 2026 and my gross monthly income dropped from $5,200 to $2,400 in unemployment benefits” gives the magistrate something to evaluate. For a three-year or 15-percent claim, the facts are numerical: the date of the last order, current gross income, prior gross income, and the percentage change.

Section 6: What You Want the Court to Do

Spell out the change you’re requesting: a lower monthly payment, a higher payment from the other party, a change in who carries health insurance, a different split of childcare costs. Vague requests get vague results. The more specific you are, the better the magistrate can act on your petition.⁴

Section 7: Arrears

If you’re current, write “NO ARREARS.” If you owe back support, enter the amount and explain why you didn’t file for modification sooner. This section matters because the court cannot cancel arrears that built up before you filed the petition, and that rule has no exceptions.² Showing “good cause” for the delay, such as illness or not understanding the process, is what this box gives you space to do.

Section 9: Support Collection Unit

Check the appropriate box if you’re applying for child support services through the Support Collection Unit, or if you already receive those services or are on public assistance. The SCU handles income withholding and other collection once an order is in place.¹

Signature

Sign and date the petition on the last page. Notarization is not required. That’s a common misconception.

Filing the Completed Petition

Submit the signed petition, an attached copy of your current support order, and Personal Information Form 4-5/5-1d to the Family Court clerk. You can file in the county where the original order was issued or the county where either party lives. Family Court does not charge a filing fee for support petitions, so you don’t need to bring money for that step.

Once the clerk accepts the filing, the court schedules a hearing date and issues a summons for the respondent.

Serving the Respondent

You cannot hand the papers to the respondent yourself. New York law requires that someone at least 18 years old and not a party to the case deliver the summons and a copy of the petition.⁵ A friend, relative, or professional process server works. So does the local sheriff’s office.

Service is completed by handing the papers directly to the respondent. If that fails, New York’s personal service statute permits alternatives, including leaving the papers with someone of suitable age at the respondent’s home or workplace and mailing a copy to their last known address.⁶ Whoever delivers the papers then completes an affidavit of service and files it with the court. Without that affidavit on file, the case cannot move forward.

Why the Filing Date Matters

A modified order can reach back only as far as the date you filed the petition. Every month you delay is a month locked into the old order.⁷ Arrears that accrued before the filing date cannot be reduced or canceled, no matter how badly circumstances changed in the months before you got the petition in.² If your income has dropped or the other party’s has climbed, fill out Form 4-11 and file it as soon as you can. Waiting costs real money.

Form 4-11 Modifies, It Does Not Enforce

Form 4-11 changes the terms of a support order. It does not punish anyone for violating the current one. If the other party owes you money and isn’t paying, you need a separate violation or enforcement petition, which invokes different court powers under FCA Section 454.⁸ The two can run at the same time on different forms; if you’re unsure which applies, the Family Court clerk’s office can point you to the right paperwork.

1
New York State Unified Court System. Family Court Form 4-11 – Petition for Modification of an Order of Support
2
New York State Senate. New York Family Court Act 451 – Continuing Jurisdiction
3
New York State Unified Court System. Financial Disclosure Affirmation – Short Form
4
New York State Unified Court System. Instructions for a Modification of an Order of Support Petition
5
New York State Unified Court System. How to Serve Papers When Commencing an Action or Proceeding
6
New York State Senate. New York Civil Practice Law and Rules Law 308 – Personal Service Upon a Natural Person
7
New York State Senate. New York Domestic Relations Law 236 – Special Controlling Provisions
8
New York State Senate. New York Family Court Act 454 – Powers of the Court on Violation of a Support Order