Support Modification Packet Forms and Instructions, pdf document. Failure to do so may result in the dismissal of your petition.1. Fill out a child support modification petition. 2. File the petition with the Family Court that most recently established your order. 3. The court will only grant a modification if there has been a substantial change in circumstances from the time of the original order. A list of Filing Fees can be found HERE. Child Support Forms. Visit the family court where your court order was issued and complete a Support Petition for Modification form (also known as Form 4-11). Org - (select) – Self Help, Family Law Forms for the forms. 2. In the absence of these to conditions, the court will not grant a child support modification.