((a)) Not later than 120 days after , the Secretary shall, in accordance with , convert to the appropriate class in the Foreign Service Schedule established under those individuals in the Foreign Service who are serving immediately before , under appointments at or below class 3 of the schedule established under section 412 or 414 of the Foreign Service Act of 1946, or at any class in the schedule established under section 415 of such Act, as—
((1)) Foreign Service officers, or
((2)) Foreign Service Reserve officers with limited or unlimited tenure, and Foreign Service staff officers or employees, who the Secretary determines are available for worldwide assignment.
((b)) Not later than 3 years after , Foreign Service Reserve officers and staff officers and employees who the Secretary determines under subsection (a)(2) are not available for worldwide assignment shall also be converted, in accordance with , to the appropriate class in the Foreign Service Schedule established under if—
((1)) the Secretary certifies that there is a need for their services in the Foreign Service; and
((2)) they agree in writing to accept availability for worldwide assignment as a condition of continued employment.