Mont. Code Ann. § 85-8-703

Before the additional powers granted by this part shall become applicable to any presently existing drainage district in this state, the commissioners of such district shall file a petition in the district court requesting such additional powers as set forth herein and proper notice shall be given to interested landowners in the same manner as in the first instance of creation of the district. Proceedings shall be conducted, insofar as possible, in accordance with the procedures set forth for determining whether or not the district shall be created in the first instance, and the district court shall render its decree or order accordingly.