Minn. Stat. § 192A.351: WITHDRAWAL OF APPEAL.

(a) In each case subject to appellate review under this code, the accused may file with the convening authority a statement expressly withdrawing the right of the accused to an appeal. A withdrawal shall be signed by both the accused and defense counsel and must be filed in accordance with appellate procedures as provided by law.

(b) The accused may withdraw an appeal at any time in accordance with appellate procedures as provided by law.