Tenn. Code Ann. § 43-38-109: Resignation of registered agent

(a) Any registered agent of a cooperative may resign as the registered agent's agency appointment by signing and filing with the secretary of state an original statement of resignation accompanied by the registered agent's certification that the registered agent has mailed a copy of the original statement of resignation to the principal office by certified mail.

(b) The agency appointment is terminated, and the registered office discontinued, if so provided, on the date on which the statement is filed by the secretary of state.