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 New Hampshire, either parent has the right to petition the court to modify a child custody order. This can be done if there is a substantial change in circumstances that affects the welfare of the child. Such changes could include alterations in the living situation, employment, health, or other significant aspects of the lives of either parent or the child. The standard for modification is centered on the best interests of the child, which is the primary consideration in custody matters. The petition to modify custody is typically filed in the court that issued the original custody order. However, if the child has since moved to a different county or state, the jurisdiction may shift to the courts where the child currently resides. This is in line with the Uniform Child Custody Jurisdiction and Enforcement Act (UCCJEA), which New Hampshire has adopted, and which dictates that the child's home state has jurisdiction over custody matters. It's important for parents to understand that modifications are not granted lightly and require a showing of substantial and continuing changes that necessitate a review of the custody arrangement.