When an employee has become physically or mentally incapable of, or unfit for, the efficient performance of the duties of his or her position, by reason of infirmities due to advanced age or other disability, the appointing authority shall recommend to the Commissioner of Administrative Services that the employee be transferred to less arduous duties or separated from state service in good standing. Any employee who is separated from state service in good standing pursuant to the provisions of this section and is subsequently reemployed within one year from the date of such separation shall be eligible to reinstate any sick leave that was accrued as of the date of such employee’s separation by repaying the entire amount of compensation such employee received as payment for such sick leave when he or she separated from state service. Such repayment shall be made in a lump sum not later than thirty days after the date of such employee’s reemployment. If such payment is not received within thirty days of the date on which such employee was reemployed, such employee shall forfeit the right to reinstate his or her accrued sick leave.