5 C.F.R. § 250.101
When taking a personnel action authorized by this chapter, an agency must comply with qualification standards and regulations issued by the Office of Personnel Management (OPM), the instructions OPM has published in the Guide to Processing Personnel Actions, and the provisions of any delegation agreement OPM has made with the agency. When taking a personnel action that results from a decision or order of OPM, the Merit Systems Protection Board, Equal Employment Opportunity Commission, or Federal Labor Relations Authority, as authorized by the rules and regulations of those agencies, or as the result of a court order, a judicial or administrative settlement agreement, or an arbitral award under a negotiated agreement, the agency must follow the instructions in the Guide to Processing Personnel Actions and comply with all other relevant substantive and documentary requirements, including those applicable to retirement, life insurance, health benefits, and other benefits provided under this chapter.
5 C.F.R. § 250.101