Okla. Stat. tit. 19 § 1607
Each person designated by a transient merchant as his agent in the application for a license shall be a resident of the county and shall be an agent of the transient merchant upon whom any process, notice, or demand required or permitted by law to be served upon the transient merchant may be served. The agent shall agree in writing to act as such agent and a copy of the agreement to so act shall be filed by the applicant with the application for a license.
The court clerk of each county shall maintain an alphabetical list of all transient merchants in the county and the names and addresses of their agents.
If any transient merchant doing business or having done business in any county within the state shall fail to have or maintain an agent in the county or if such agent cannot be found at his permanent address, the court clerk shall be an agent of such transient merchant for service of all process, notices, or demands. Service on the court clerk shall be made by delivery to and leaving with him or any person designated by the clerk to receive such service, duplicate copies of the process, notice, or demand. When any such process, notice, or demand is served on the clerk, he shall immediately cause one copy thereof to be forwarded by registered or certified mail, return receipt requested, to the permanent address of the transient merchant. The provisions of this section shall not limit or otherwise affect the right of any person to serve any process, notice, or demand in any other manner now or hereafter authorized by law.
Okla. Stat. tit. 19, § 1607