Except as otherwise provided in Section 152.204, 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 152.201(a)(1) or (2) and:
(1) the court of the other state determines it no longer has exclusive continuing jurisdiction under Section 152.202 or that a court of this state would be a more convenient forum under Section 152.207; 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.
Official text of the Texas Family Code as published by the Texas Legislative Council.