It is always best to get the consent of the other parent. If there is any doubt that it will be questioned, it is always best to file a motion for approval of the court.
This answer is provided for informational purposes only. Actual legal advice can only be provided in an office consultation by an attorney licensed in your jurisdiction, with experience in the area of law in which your concern lies.
Absent an Order to the contrary, there is nothing that requires a parent to seek consent of the other to take the child out of state for vacation.
If the other parent does not return, you can seek an ex parte order to have the chuildren immediately returned and seek a change of custody.
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