This Easy Form helps you ask the court to increase or decrease your current child support order. This is called child support modification.Form: Petition for Modification of Child Support. First blank: Your name. This document is a sample form letter designed for individuals seeking a downward modification of their child support obligations. Download a free child support modification form to propose changes to a current child support agreement. Available in PDF or Word format. Yes, you can write your child support modification letter using our templates or form builder, which will guide you through the creation process. Download and complete Divorce, Child Support, and Maintenance forms from the Illinois Office of the Courts. To file such a motion, you generally need to explain the change in circumstances that have taken place which warrant changing the current support order.