You can register your existing custody order in Colorado, which then allows a Colorado court to enforce it and, in some cases, consider modifications. Registration typically requires certified copies of the order and filing in the district where you or the other parent lives. Once registered, enforcement tools under the UCCJEA can be used if violations occur. These steps help maintain continuity for the child when crossing state lines. The Judicial Branch provides instructions and forms for registration. See the registration page and UCCJEA references for specifics.