32 C.F.R. § 21.450
What are the requirements for a termination of a grants officer's or agreements officer's appointment?
A termination of a grants officer's or agreements officer's authority:
(a) Must be in writing, unless the written statement of appointment provides for automatic termination.
(b) May not be retroactive.
(c) May be integrated into a written termination of the individual's appointment as a contracting officer, as appropriate.