Minn. Stat. § 145C.09
Subd. 1. Revocation.
A principal with the capacity to do so may revoke a health care directive in whole or in part at any time by doing any of the following:
Subd. 2. Effect of dissolution or annulment of marriage or termination of domestic partnership on appointment of health care agent.
Unless the principal has otherwise specified in the health care directive, the appointment by the principal of the principal's spouse or registered domestic partner as health care agent under a health care power of attorney is revoked by the commencement of proceedings for dissolution, annulment, or termination of the principal's marriage or commencement of proceedings for termination of the principal's registered domestic partnership.
Subd. 3. Power of a guardian.
The powers of a guardian to revoke the appointment of a health care agent in a health care directive of which the ward is the principal or to revoke the health care directive itself are specified in section 524.5-315.