Okla. Stat. tit. 18, § 589

Before being competent to so receive such property, such society shall obtain a charter as a charitable corporation in the manner provided by law from the Secretary of State, and elect trustees, who may be the same trustees already elected under their fraternal rules, and whose bylaws may, so far as they do not contravene the statute laws of the state, be substituted for the bylaws required to be adopted upon obtaining a charter.