Once a custody and placement order is in place, it is presumed to be in the best interests of the children to maintain the status quo of the order. You would need to establish that there has been a substantial change in circumstances since the entry of the last order, and that it has been at least two years from entry of the final judgemennt (if not 2 years, then you must prove it is harmful to the child to maintain status quo).
That being said a move of 25 miles is not a substantial change in circumstances according to case law. There may be other things you can establish, you would need to meet with an attorney to walk you through all of the potential changes that happened and what would qualify to be a substantial change.
You need to meet with an attorney in this matter.
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