49 CFR § 551.52
How long will a foreign manufacturer's designation of agent remain in effect?
November 18, 2020
(a) A designation of agent remains in effect until replaced or withdrawn by a foreign manufacturer.
(b) A foreign manufacturer that has withdrawn but not replaced its agent may not continue to import motor vehicles or motor vehicle equipment into the United States. In order to do so, it must appoint a new agent in accordance with the requirements of this subpart.