5 C.F.R. § 536.101
This part contains OPM regulations for the administration of grade and pay retention. This part supplements and implements the provisions of 5 U.S.C. 5361-5366 and must be read together with those sections of law. Under 5 U.S.C. 5362 , an employee under a covered pay system who is placed in a lower grade (e.g., as a result of a reduction in force or when his or her position is reduced in grade as a result of a reclassification) is entitled to retain the grade held immediately before the reduction for a period of 2 years under the circumstances prescribed in this part. Under 5 U.S.C. 5363 , an employee whose rate of basic pay otherwise would be reduced as a result of a management action is entitled to retain his or her rate of basic pay under the circumstances prescribed in this part.
5 C.F.R. §536.101