Mont. Code § 21
If the parties to an appeal or other proceeding shall sign and file with the clerk an agreement that the proceeding be dismissed, specifying the terms as to payment of costs, and shall pay whatever fees are due, the clerk shall enter the case dismissed, and shall give to each party a copy of the agreement filed; but no mandate or other process shall issue without an order of the court. An appeal may be dismissed on motion of the appellant upon such terms as to costs as may be agreed upon by the parties or fixed by the court. If an appeal has not been docketed the appeal may be dismissed by the court from which the appeal was taken upon the filing in that court of a stipulation for dismissal signed by all parties, or upon motion and notice by the appellant. The clerk of the municipal court shall mail a copy of the order of dismissal to the clerk of the district court.
§ 21, MCA