Petitioning the Court
In most cases, you must file a petition or motion for modification in the court that has jurisdiction over your divorce decree, i.e. the court that originally handled your divorce action. In the case of child support, either the custodial or noncustodial parent can file the petition. It is not necessary to have an attorney assist you in drawing up or filing the motion, but legal representation may be helpful if you need to argue the grounds for modification or if the motion is contested by your former spouse.
A change in circumstances is not always sufficient grounds for modifying a support order. If you are paying the support, you must provide compelling evidence that you will be unable to meet the obligation for an indefinite period of time. If you are receiving the support, you must prove that changed circumstances in your own household justify the modification. In the case of child support, some states go strictly by their support guidelines; Vermont, for example, allows modification if a revised calculation using these guidelines results in a difference of at least 10 percent in the amount of child support that should be paid. Alternately, you may show that providing the originally ordered support amount is detrimental to the interests of another person, such as a child whom you now must support in your own household. Some states also allow modification when the custodial parent undergoes an improvement in her circumstances, such as a remarriage that substantially improves her financial condition.
Along with the motion, you will likely have to file a new calculation according to the support guidelines in your state. In most states, this comes in the form of a worksheet that you can download from an official court website (state attorney general offices also may provide this online). You can also obtain a worksheet in hard copy form from the court clerk; some states offer an online calculator to assist in this process. You will need a large set of data, including current income, health insurance costs, medical costs, household expenses, debts, education costs, and other financial factors of both households. Along with the worksheet, you must file supporting evidence, which may include W-2s, tax returns, documentation of unemployment or disability benefits, or any other document that will help your claim that the support amount should be changed.
As petitioner, you must have the motion, guidelines and any supporting documents served on the other party, known as the respondent. This can be done through a private process server or through a law enforcement agency, such as a county sheriff's department. There is a deadline for service after the motion is filed – in most jurisdictions, this is 20 or 30 days. If you are unable to have the papers served, you must file for an extension of time to do so. Once service has been effected, you must file proof of service with the court showing you have carried out this important step.
Hearing and Adjudication
The respondent has the right to file an answer within the statutory deadline – again, usually 20 or 30 days. Both spouses must attend a public hearing on the motion, during which a judge will review the documents and decide on the motion. If you no longer live within the jurisdiction of the court, you may (in some cases) petition to appear by telephone. If the respondent contests the motion, the judge will hear both sides and pose questions, if necessary, to determine the proper outcome. The motion may be approved or denied; a judge may also use his discretion in modifying the support order by a compromise. Until the court adjudicates the motion, the prior support order remains in effect and any arrearages continue to accrue.