48 CFR § 15.206 - Amending the solicitation.
(a) When, either before or after receipt of proposals, the Government changes its requirements or terms and conditions, the contracting officer shall amend the solicitation.
(b) Amendments issued before the established time and date for receipt of proposals shall be issued to all parties receiving the solicitation.
(c) Amendments issued after the established time and date for receipt of proposals shall be issued to all offerors that have not been eliminated from the competition.
(d) If a proposal of interest to the Government involves a departure from the stated requirements, the contracting officer shall amend the solicitation, provided this can be done without revealing to the other offerors the alternate solution proposed or any other information that is entitled to protection (see 15.207(b) and 15.306(e)).
(e) If, in the judgment of the contracting officer, based on market research or otherwise, an amendment proposed for issuance after offers have been received is so substantial as to exceed what prospective offerors reasonably could have anticipated, so that additional sources likely would have submitted offers had the substance of the amendment been known to them, the contracting officer shall cancel the original solicitation and issue a new one, regardless of the stage of the acquisition.
(f) Oral notices may be used when time is of the essence. The contracting officer shall document the contract file and formalize the notice with an amendment (see subpart 4.5, Electronic Commerce in Contracting).
(g) At a minimum, the following information should be included in each amendment:
(1) Name and address of issuing activity.
(2) Solicitation number and date.
(3) Amendment number and date.
(4) Number of pages.
(5) Description of the change being made.
(6) Government point of contact and phone number (and electronic or facsimile address, if appropriate).
(7) Revision to solicitation closing date, if applicable.