Who must follow these requirements?

§ 81.50 Who must follow these requirements? Any tribe meeting the criteria in paragraphs (a) or (b) of this section must follow the requirements of this subpart. (a) A tribe whose governing document or charter of incorporation provides for petitioning the Secretary to call a Secretarial election for any of the following purposes: (1) Amending or revoking the governing document; (2) Amending a charter of incorporation ratified under 25 U.S.C. 477 of the IRA before May 24, 1990 where the amendments section or article specifically requires it; (3) Amending or ratifying a charter of incorporation under 25 U.S.C. 503 of the OIWA; or (4) Taking any other action authorized by the governing document or charter of incorporation. (b) A federally recognized tribe, without an existing governing document, adopting a governing document under Federal statute, for the first time.