If you and your spouse or ex-spouse are having issues with child custody, it's a good idea to sit down and talk through the problems you're having. If your custody schedule isn't working for you or one of you wants more custody, then you may want to think about how you can be accommodating or what you can do to make the situation better.
With your original custody order, for example, you may have set up a 50-50 custody plan where you each see your child for two weeks at a time. That might have worked when your child was younger, but now that they're in school and busier, it doesn't make sense to have them go between homes during the school week. If you need to modify your schedule, it's possible to do so (and easier to do so if you both agree on a new schedule).