Okla. Stat. tit. 43A, § 43A-11-111: Petition for appointment of guardian

Any person may petition the district court for appointment of a

guardian for a declarant when the person has good reason to believe

that the provision of mental health treatment in a particular case:

1. Is contrary to the most recent expressed wishes of a

declarant who was capable at the time of expressing the wishes;

2. Is being proposed pursuant to an advance directive for

mental health treatment that has been falsified, forged, or coerced;

or

3. Is being considered without the benefit of a revocation

which has been unlawfully concealed, destroyed, altered or canceled.