14 CFR § 152.321
Notice of delay or acceleration
July 13, 2020
(a) The sponsor or planning agency shall promptly notify the FAA of each condition or event that may delay or accelerate accomplishment of the project.
(b) In the event that delay is anticipated, the notice required by paragraph (a) of this section must include—
(1) A statement of actions taken or contemplated; and
(2) Any Federal assistance needed.