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 Oregon, child support orders can be modified if there has been a 'material and substantial change' in the circumstances of the child or either parent since the last order was made. This could include significant changes in income, the needs of the child, or the parenting time arrangement. Additionally, Oregon law allows for a review of child support orders every three years, at which time the support amount can be adjusted to reflect current circumstances without the need to prove a substantial change. If there is a change in custody, such as the noncustodial parent becoming the custodial parent, this would also constitute a material and substantial change that could lead to the modification or termination of the child support obligation. To initiate a modification, the parent must file a motion to modify with the court, and the court will evaluate the evidence presented to determine if a modification is warranted.