22 USC 3948 - Recall and reappointment of career members

(a) Retired career members 
Whenever the Secretary determines that the needs of the Service so require, the Secretary may recall any retired career member of the Service for active duty in the same personnel category as that member was serving at the time of retirement. A retired career member may be recalled under this section to any appropriate salary class or rate, except that a retired career member of the Senior Foreign Service may not be recalled to a salary class higher than the one in which the member was serving at the time of retirement unless appointed to such higher class by the President, by and with the advice and consent of the Senate.
(b) Former career members 
Former career members of the Service may be reappointed under section 3942 (a)(1) or 3943 of this title, without regard to section 3946 of this title, in a salary class which is appropriate in light of the qualifications and experience of the individual being reappointed.