1-16-501. Proceeding against parties not summoned and persons whose liability unknown. When judgment is rendered in this state on a joint instrument, parties to the action who were not summoned and persons whose liability was not known to the plaintiff at the rendition of the judgment may be made parties thereto by action in the same court if they can be summoned. When the judgment is rendered elsewhere, the plaintiff may bring suit upon the instrument against the parties not summoned or persons whose liability was unknown, in any county where any of the parties reside or may be summoned.
Wyoming Legal Code