CFR›Title 48›Chapter 6›Part 643 ContainsSubpart 643.1CorpusDaily eCFRDisplayed edition2026-05-08Last updated2026-05-08 PART 643—CONTRACT MODIFICATIONS Subparts 643.1 Subpart 643.1—General Sections 643.102–643.104-70 Authority40 U.S.C. 486(c); 22 U.S.C. 2658.Source53 FR 26176, July 11, 1988, unless otherwise noted. Previous 642 Part 642—Contract Administration and Audit Services Next 644 Part 644—Subcontracting Policies and Procedures