Minn. R. Civ. P. 9.08
As amended through October 28, 2024
When a party is ignorant of the name of an opposing party and so alleges in the party's pleading, the opposing party may be designated by any name and when that opposing party's true name is discovered the process and all pleadings and proceedings in the action may be amended by substituting the true name.
Minn. R. Civ. P. 9.08