Either parent may file a petition to modify a child custody order—but usually only when there is a substantial change in circumstances that affects the child (including changes in one or both of the parents’ lives) that justifies the court revisiting and possibly modifying the earlier child custody order.

The petition to modify child custody generally must be filed in the same court in which the parents’ divorce case was decided. But if the child lives in a different county or state, the courts of the county or state where the child lives may be the proper place to file a petition to modify a child custody order.

In Delaware, either parent has the right to file a petition to modify a child custody order. This can be done if there is a substantial change in circumstances that significantly affects the child's well-being. Such changes could include alterations in the living situation, financial status, or other relevant aspects of one or both parents' lives. The court will consider whether the modification serves the best interests of the child. Typically, the petition must be filed in the same court where the original divorce and custody decisions were made. However, if the child has since moved to a different county or state, the petition may need to be filed in the court that has jurisdiction over the child's new residence. It's important to note that the laws governing child custody modifications can be complex, and an attorney can provide guidance specific to the circumstances of the case.