Tenn. Code Ann. § 48-15-103: Resignation of registered agent

(a) A registered agent may resign 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 thereof to the principal office of the corporation by certified mail. The statement may include a statement that the registered office is also discontinued.

(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.