- Two parents have in force a child custody agreement (a/k/a Parenting Plan, PP) in U.S. state X.
- The PP stipulates shared residential time with their minor child between the parents per a specific schedule.
- PP contains no unusual provisions.
- Parent A violates the PP and moves the child out of state (to U.S. state Y).
Under what circumstances (if any) can parent A ever obtain legal custody of the child without physically returning to court in state X?
If the values of X and Y matter in the answer, feel free to choose (and specify) them for yourself.