Mont. Code Ann. § 25-4-312

When an action is filed in the district court to recover damages for personal injury or wrongful death, the parties against whom the action is brought may at any time request a statement setting forth the nature and amount of damages being sought. The request shall be filed and served upon the claimant, who shall file and serve a responsive statement as to damages within 15 days thereafter. In the event that a response is not served, the party, on notice to the claimant, may petition the court in which the action is pending to order the claimant to serve a responsive statement.