48 C.F.R. § 315.204-5 – Part IV—Representations and instructions.

(c) Section M, Evaluation factors for award.
(1) The requiring activity shall develop technical evaluation factors and submit them to the contracting officer as part of the acquisition plan or other acquisition request documentation for inclusion in a solicitation. The requiring activity shall indicate the relative importance or weight of the evaluation factors based on the requirements of an individual acquisition.
(2) Only a formal amendment to a solicitation can change the evaluation factors.