In the case of any individual in the Foreign Service who, immediately before February 15, 1981, is serving under an appointment described in section
4152
(a) or
4153
(a) of this title and who is not converted under section
4152 or section
4153 of this title because such individual does not meet the conditions specified in section
4152
(b) or
4153
(d) of this title, the Secretary shall, not later than 3 years after February 15, 1981, provide that—