When a parent needs to relocate but has a child with his or her ex-spouse, it can make it hard to do so without changing custody arrangements. That doesn't always go well, depending on the concerns of the other parent. No parent has a right to take a child to a new home or location without consent, unless there is a release from the court.
If there is express consent in your custody arrangements, then you may have a right to move as long as it is within the terms of the original agreement. If you do not have consent, then you will need to give notice to the noncustodial parent with your intention to move. It's a good idea to give the other parent notice as soon as possible, but usually at least within 30 to 90 days.
The other parent may object to the move in most cases by filing a motion to prevent you from relocating.You may have to provide information on why you need to move in good faith. This is particularly common if you're going to disrupt your child's schooling by moving. Some reasons the court may accept include having a better cost of living, being closer to your family, getting a new job or going to school to further your education.
The reality of this situation is that it's hard for everyone. Moving away from one parent is never easy for a child or the parent losing valuable time with his or her child. Still, if you must move, having good evidence of the reasoning behind your choice can help you get the approval to do so.