Okla. Stat. tit. 63, § 63-3101.5: Advance directive - When and which become operative

A. An advance directive becomes operative when:

1. It is communicated to the attending physician; and

2. The declarant is no longer able to make decisions regarding

administration of life-sustaining treatment. When the advance

directive becomes operative, the attending physician and other

health care providers shall act in accordance with its provisions or

comply with the provisions of Section 9 of this act.

B. In the event more than one valid advance directive has been

executed and not revoked, the last advance directive so executed

shall be construed to be the last wishes of the declarant and shall

become operative pursuant to subsection A of this section.