41 CFR 301-70.200: -70.200 Governing policies for subsistence expenses authorization and payment.

Agencies must establish policies and procedures governing—

(a) Who will authorize a rest period;

(b) Circumstances allowing a rest period during prolonged travel (see § 301-11.12 of this chapter for minimum standards);

(c) What constitutes a rest period upon arrival at a temporary duty location;

(d) If, and in what instances, the agency will allow an employee to return to the official station on non-workdays;

(e) Who will determine if an employee will be allowed to return to the official station on a case-by-case basis;

(f) Who will determine in what instances the agency will pay a reduced per diem rate;

(g) Who will determine, and in what instances, to issue a blanket actual expense authorization under § 301-70.201;

(h) What circumstances necessitate the extension of a blanket actual expense authorization under § 301-70.201; and

(i) Who may submit requests for per diem rate reviews on behalf of the agency.