41 CFR § 301-11.3
Must my agency pay an allowance (either a per diem allowance or actual expense)?
June 9, 2020
Yes, unless:
(a) You perform travel to a training event under the Government Employees Training Act (5 U.S.C. 4101-4118), and you agree not to be paid per diem expenses; or
(b) You perform pre-employment interview travel, and the interviewing agency does not authorize payment of per diem expenses.