Parties can modify an agreement orally, by their actions or by a written exchange. If you want to enforce an agreement that was created in one of these ways, you should have good success. However, all of these kinds of agreements leave much open to interpretation. If there are specific items you want to enforce, you should set those out in a written agreement so that there is no ambiguity. If you want a guide for a proposed custody order click on my blog “Custody Order” below.