If you would like to change a child support or custody order that resulted from a SAPCR, you will need to file with the court for a modification. 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. A modification in San Antonio changes the terms of the contract after it has been signed. Downloadable forms for eFiling, Divorces, and Suites Affecting the Parent-Child Relationship, Child Support, Hail Claims, Legal, LegalEase, and Passports. Talk to the San Antonio attorneys at Grable Grimshaw PLLC about an order modification. We can also help if you need assistance in enforcing an existing order. Step 1: Fill out your court forms. Fill out the following starting forms: â—‹ Petition to Modify the Parent-Child Relationship. File a petition with the clerk's office to initiate the modification process.