Minn. Stat. § 351.055

If a future vacancy becomes certain to occur and the vacancy must be filled by a special election, the appropriate authorities may begin procedures leading to the special election so that a successor may be elected at the earliest possible time. For prospective vacancies that will occur as a result of a resignation, preparations for the special election may begin immediately after the written resignation is received by the official provided in section 351.01, subdivision 1 .