Mont. Code Ann. § 81-8-315

When an officer into whose hands a writ of execution is placed has served the writ in accordance with 81-8-311 and made a return in accordance with the facts, at any time after service and return, within the time limited as provided in 81-8-313 to hold the property taken or levied upon under the writ, another writ of execution may be issued, which must be supplementary to the first writ, and in pursuance of which the officer or person charged with the service of the substitute writ may sell the property held by the first writ as provided in this part.