Mich. Comp. Laws § 722.1202

Sec. 202. (1) Except as otherwise provided in section 204, a court of this state that has made a child-custody determination consistent with section 201 or 203 has exclusive, continuing jurisdiction over the child-custody determination until either of the following occurs: (a) A court of this state determines that neither the child, nor the child and 1 parent, nor the child and a person acting as a parent have a significant connection with this state and that substantial evidence is no longer available in this state concerning the child's care, protection, training, and personal relationships. (b) A court of this state or a court of another state determines that neither the child, nor a parent of the child, nor a person acting as the child's parent presently resides in this state. (2) A court of this state that has exclusive, continuing jurisdiction under this section may decline to exercise its jurisdiction if the court determines that it is an inconvenient forum under section 207. (3) A court of this state that has made a child-custody determination and that does not have exclusive, continuing jurisdiction under this section may modify that child-custody determination only if it has jurisdiction to make an initial child-custody determination under section 201.