In general, to change a court order, you need to file a motion. When it comes to taxes, a court order may not be relevant. According to the IRS, federal law determines who can claim a child as a dependent on federal income taxes. If a noncustodial parent were granted the right to claim a child by a court order, the custodial parent would need to return Form 8332 or a similar document. If the custodial parent wants to claim the child, however, they have the right to do so under federal law if the child lives with them the majority of the time.