49 CFR § 366.6 - Cancellation or change.
(a) A designation may be canceled or changed only by a new designation made by the motor carrier, broker, or freight forwarder, or by the process agent or company filing a blanket designation in accordance with § 366.5. However, where a motor carrier, broker or freight forwarder's USDOT Number is inactive for at least 1 year, designation is no longer required and may be canceled without making another designation.
(b) A change to a designation, such as name, address, or contact information, must be reported to FMCSA within 30 days of the change.
(c) Whenever a motor carrier, broker or freight forwarder changes it name, address, or contact information, it must report the change to its process agents and/or the company making a blanket designation on its behalf in accordance with § 366.5 within 30 days of the change.
(d) Whenever a process agent and/or company making a blanket designation on behalf of a motor carrier, broker, or freight forwarder terminates its contract or relationship with the entity, it should report the termination to FMCSA within 30 days of the termination. If process agents and/or blanket agents do not keep their information up to date, FMCSA may withdraw its approval of their authority to make process agent designations with the Agency.