Mont. Code Ann. § 82-1-203

At least 20 days before bringing the action provided for in this part, the owner of the leased land, either personally or by the owner's agent or attorney, shall demand of the holder of the lease, if the demand by ordinary diligence can be made in this state, that the lease or abstract of the lease be released of record. The demand must be written. When written, a copy, when shown to be a copy, may be used as evidence in any court with the same force and effect as the original.