7 GCA § 39203: Jurisdiction to Modify Determination.

Except as otherwise provided in section 39204, the Superior Court of Guam may not modify a child-custody determination made by a court of another State unless the Superior Court of Guam has jurisdiction to make an initial determination under section 39201(a)(1) or (2) and:

(1) the court of the other State determines it no longer has exclusive, continuing jurisdiction under section 39202 or that the Superior Court of Guam would be a more convenient forum under section 39207; or

(2) the Superior Court of Guam 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.