Okla. Stat. tit. 68 § 236
The Tax Commission may prescribe rules and regulations governing the recognition of agents, accountants, attorneys, or other persons representing taxpayers before the Tax Commission, and may require that such person, before being recognized as representatives of taxpayers, shall make a proper showing that they are of good character and in good repute and are possessed of the necessary qualifications to enable them to render such taxpayers valuable services, and are otherwise competent to advise and assist such taxpayers in the preparation of reports, returns or cases to be filed with or heard before the Tax Commission. The Tax Commission may, after due notice and an opportunity for hearing, suspend and disbar from further practice before the Tax Commission any such person, agent, accountant or attorney shown to be incompetent or disreputable or who refuses to comply with the said rules and regulations, or who shall, with intent to defraud, in any manner willfully and knowingly deceive, mislead, or threaten any taxpayer or prospective client by words, circular, letter, or by advertisement, or who shall advise a taxpayer to file a fraudulent or false report or return, or who shall prepare a false or fraudulent report or return in any particular whatsoever, or who shall assist, aid or abet any taxpayer in concealing any information pertaining to said taxpayer's books, records, reports or returns, or who shall delay proceedings of the Tax Commission to assist a taxpayer in disposing of or concealing property upon which a levy could be made for the collection of taxes accrued, or who shall be in default in payment of taxes or filing reports or returns under any state tax law.
Okla. Stat. tit. 68, § 236