Okla. Stat. tit. 40 § 4-109
If the Oklahoma Employment Security Commission is sued, or if its officers or employees are sued in their official capacities, the service of all legal process pursuant to Section 2004 of Title 12 of the Oklahoma Statutes and of all extrajudicial notices which may be required in writing shall be made on the Executive Director at the official office of the Commission as set out in Administrative Rule 240:1-1-5. This section shall not apply to appeals brought under Article 2, Part 6 and Article 3, Part 4 of the Employment Security Act of 1980. Service of process in Article 2, Part 6 and Article 3, Part 4, shall be made pursuant to the procedures set out by the statutes in those parts and the administrative rules implementing those statutes. This section shall not be construed to waive any immunity created by constitution or statute that applies to the Oklahoma Employment Security Commission, its officers or employees or this state.
Okla. Stat. tit. 40, § 4-109