Iowa Code § 598B.203: Jurisdiction to modify determination.

Except as otherwise provided in section 598B.204, a court of this state shall 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 598B.201, subsection 1, paragraph “a” or “b”, and either of the following applies:

1. The court of the other state determines it no longer has exclusive, continuing jurisdiction under section 598B.202 or that a court of this state would be a more convenient forum under section 598B.207.

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.