Child Support Forms ; 4-3b. Addendum to Support Petition– Request for Child Support (IV-D) Services.It is not so hard if you go fill out paperwork from the court. Write the letter spelling out the time line and chronicle the events of your child being taken out of state without your knowledge and permission. The child support program operates on an interstate basis and therefore requires close federal, state, and tribal cooperation. Use our printable child support demand letter template to require someone to pay their owed child support. Download it for free here. A modification of a child support order may be requested if there has been a substantial change of circumstances since the order was entered. A custodial parent can waive or forgive all arrears owed to him or her directly. This handbook provides information regarding applying for child support services, locating the non-custodial parent.