49 C.F.R. § 375.605
(a) When you are unable to perform either the pickup or delivery of a shipment on the dates or during the periods specified in the bill of lading and as soon as the delay becomes apparent to you, you must notify the individual shipper of the delay, at your expense, in one of the following six ways:
(b) You must advise the individual shipper of the dates or periods you expect to be able to pick up and/or deliver the shipment. You must consider the needs of the individual shipper in your advisement. You also must do the following four things:
[68 FR 35091, June 11, 2003, as amended at 69 FR 10576, Mar. 5, 2004; 87 FR 24448, Apr. 26, 2022]