Download a free child support modification form to propose changes to a current child support agreement. Available in PDF or Word format.Here's what to expect when you request for a modification of your child support order. Click here to learn the steps in the modification journey. Step 1: Fill out your court forms. Fill out the following starting forms: â—‹ Petition to Modify the Parent-Child Relationship. This document is a sample form letter designed for individuals seeking a downward modification of their child support obligations. Yes, you can write your child support modification letter using our templates or form builder, which will guide you through the creation process. Qualified Medical Child Support Order. To enroll, please complete an application and send it to Tarrant County Child Support Services.