Montana New Filing Additional Party is a process used to add a new party to a legal action that has already been filed with the court. This process is used if a plaintiff or defendant is added to an existing legal action that was originally filed without them. There are two types of Montana New Filing Additional Party: a complaint to add a party, and an amendment to add a party. A complaint to add a party is used when a plaintiff or defendant is added to a case that was originally filed without them. An amendment to add a party is used when a defendant is added to a case that has already been filed which includes a plaintiff. Both types of Montana New Filing Additional Party require the filing of the appropriate court forms, payment of the filing fees, and service of process upon the newly added party.