When the court issues a child custody order,the arrangement is based on your circumstances at that time. We all know that circumstances can – and do – change, and even if you and the other parent agreed to a schedule at the time, the schedule may no longer work. Abiding by the schedule might become overly stressful, impractical, or even impossible over time. The good news is that the law allows you to modify your child custody arrangement when the court deems it necessary.