S.C. Code § 9-9-67
Should the system report and certify to the board that such disability beneficiary is engaged in or is able to engage in a gainful occupation paying more than the difference between his retirement allowance and his earnable compensation and should the board concur in such report, the amount of his employer annuity shall be reduced to an amount which, together with his employee annuity and the amount earnable by him, shall equal the amount of his earnable compensation. Should his earning capacity be later changed, the amount of his employer annuity may be further modified. The new employer annuity shall not exceed the amount of the employer annuity originally granted nor an amount which, when added to the amount earnable by the beneficiary together with his employee annuity, equals the amount of his earnable compensation.
S.C. Code § 9-9-67