Supplemental Petition for Modification of Child Support. Form Number 12.905(b).❖ Copy of Final Judgment or Order you are requesting to modify. ❖ Copy of Petitioner and Respondents Driver's (copies must be enlarged and clear). This form should be used when you are asking the court to change a current court-ordered child support obligation. If you need to change your direct deposit, complete a new enrollment form and follow the given instructions. How to Change a Support Order. Your child support order amount is based on the income of both parents and the needs of the child. Step-by-step guide on completing and filing a motion to modify child support based on changed circumstances like income, custody, or expenses. (The clerk will also require you to fill out a short financial affidavit in addition to this form.) †.