5 CFR 531.241: Retaining and losing GM status.

(a) An employee retains status as a GM employee (as defined in § 531.203) when detailed to any position or when reassigned to another GS position in which the employee continues to be a supervisor or management official (as defined in 5 U.S.C. 7103(a)(10) and (11)).

(b) An employee permanently loses status as a GM employee if he or she is promoted (including a temporary promotion), transferred, demoted, reassigned to a position in which the employee will no longer be a supervisor or management official, has a break in service of more than 3 days, or becomes entitled to a retained rate under 5 CFR part 536. (A retained grade is not considered in determining whether a GM employee has been reduced in grade. See 5 CFR 536.205.)