C.R.S. § 14-13-203: Jurisdiction to modify determination.

(1) Except as otherwise provided in section 14-13-204, a court of this state may not modify a child-custody determination made by a court of another state unless a court of this state has jurisdiction to make an initial determination under section 14-13-201 (1)(a) or 14-13-201 (1)(b) and:

(a) The court of the other state determines it no longer has exclusive, continuing jurisdiction under a provision of law adopted by that state that is in substantial conformity with section 14-13-202 or that a court of this state would be a more convenient forum under a provision of law adopted by that state that is in substantial conformity with section 14-13-207; or

(b) A court of this state or a court of the other state determines that the child, the child's parents, and any person acting as a parent do not presently reside in the other state.