(a)  The Secretary may pursuant to a recommendation of the Foreign Service Grievance Board, an equal employment opportunity appeals examiner, or the Special Counsel of the Merit Systems Protection Board, and shall pursuant to a decision or order of the Merit Systems Protection Board⁠—

(1)  recommend to the President a promotion of a member of the Service under section 3942(a) of this title;

(2)  promote a member of the Service under section 3943 of this title;

(3)  grant performance pay to a member of the Senior Foreign Service under section 3965(c) of this title; or

(4)  grant a within-class salary increase under section 3966 of this title to a member of the Service who is assigned to a salary class in the Foreign Service Schedule.

(b)  In implementing subsection (a) of this section and in cases in which the Secretary has exercised the authority of section 4005(b) of this title, the Secretary may, in special circumstances set forth by regulation, make retroactive promotions, grant performance pay, make retroactive within-class salary increases, and recommend retroactive promotions by the President.