Mont. Code Ann. § 40-7-307

If a proceeding for enforcement under this part is commenced in a court of this state and the court determines that a proceeding to modify the determination is commenced in a court of another state having jurisdiction to modify the determination under 40-7-105, 40-7-107 through 40-7-110, 40-7-112, and part 2 of this chapter, the enforcing court shall immediately communicate with the modifying court. The proceeding for enforcement continues unless the enforcing court, after consultation with the modifying court, stays or dismisses the proceeding.