UCCJEA § 203. Jurisdiction to Modify Determination
Except as otherwise provided in Section 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 201(a)(1) or (2) and:
(1) the court of the other State determines it no longer has exclusive, continuing jurisdiction under Section 202 or that a court of this State would be a more convenient forum under Section 207; or
(2) 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.