S.C. Code Ann. § 5-3-40

Whenever it is proposed to extend the corporate limits of any municipality by inclusion of territory of another adjacent municipality in whole or in part, the governing bodies of the municipalities may, after public hearing, stipulate and agree upon terms of consolidation or boundary adjustment by ordinance adopted by each municipality, which shall be binding upon the enlarged municipality, and the consolidation or adjustment shall be effective on the date of adoption of the final ordinance.