S.D. Codified Laws § 3-12C-1404
If a retired member whose benefits have been reduced pursuant to § 3-12C-1111 becomes employed as a permanent full-time employee by a participating unit on or after July 1, 2004, but before April 1, 2010, the member's monthly retirement benefit must be reduced by fifteen percent and the COLA must be eliminated throughout the period that the member reenters covered employment. If the member remains in reemployment for at least three years pursuant to the provisions of § 3-12C-1403, the member upon subsequent retirement must receive an additional benefit based upon the member's credited service and final average compensation earned during the reentry. Only the member's credited service from the subsequent employment must be taken into account in calculating a reduction pursuant to § 3-12C-1111, if any, in the member's additional benefit. If the member remains in reemployment for a period of less than three years, the member upon subsequent retirement must receive a refund of the member's accumulated contributions. No matter the duration of the member's reemployment, the COLA applied to the original benefit pursuant to § 3-12C-703 must be eliminated for the period of reemployment.
SDCL 3-12C-1404