Mo. Rev. Stat. § 456.1010
Power to revoke or amend.
456.1010. Power to revoke or amend. — A donor may revoke or amend a power of appointment only to the extent that the instrument creating the power is revocable by the donor, or the donor reserves a power of revocation or amendment in the instrument creating the power of appointment.
(L. 2016 H.B. 1765)