Child support generally may be changed or modified by filing a motion to modify and demonstrating to the court that the circumstances of the child or one or both parents have materially and substantially changed, or that some period of time (3 years, for example) has passed since the court’s last child support order. And if there has been a material and substantial change in the custody of the child—if, for example, the noncustodial parent who was paying child support has become the custodial parent—the court may change or eliminate the child support obligation based on the change in the custody arrangement.

In New York, child support orders can be modified if there has been a 'substantial change in circumstances' since the original order was issued. This could include significant changes in either parent's income, the needs of the child, or the living arrangements of the child. Additionally, New York law provides that either parent can seek modification of a child support order if three years have passed since the order was entered or last modified, or if there has been a change in either parent's gross income by fifteen percent or more since the order was entered or last modified. If the noncustodial parent becomes the custodial parent, this change in custody can be grounds for the court to modify or terminate the child support obligation. To initiate a modification, the parent must file a petition with the court that issued the original child support order, and the court will evaluate the evidence presented to determine if a modification is warranted.