Okla. Stat. tit. 63, § 63-3111.4: Revocation

A. An individual may revoke the designation of an agent by a

signed writing or by personally informing the health care provider

at any time and in any manner that communicates an intent to revoke.

B. A health care provider or agent who is informed of a

revocation shall promptly communicate the fact of the revocation to

the attending physician and to any health care facility at which the

patient is receiving care.

C. A decree of annulment, divorce, dissolution of marriage, or

legal separation revokes a previous designation of a spouse as agent

unless otherwise specified in the decree or specifically enumerated

in a power of attorney for health care.

D. A power of attorney for health care that conflicts with an

earlier power of attorney for health care revokes the earlier power

of attorney to the extent of the conflict.