S.C. Code Ann. § 58-5-330

Within twenty days after an order or decision is made by the commission, any party to the action or proceeding may apply for a rehearing as to any matter determined in the action or proceeding and specified in the application for rehearing and a rehearing must be granted if in the judgment of the commission sufficient reason exists. No right of appeal arising out of an order or decision of the commission accrues in any court to any corporation or person unless the corporation or person makes application to the commission for a rehearing within the time specified. The application must set forth specifically the ground on which the applicant considers the decision or order to be unlawful. The determination must be made by the commission within thirty days after it is finally submitted. If, after the hearing and a consideration of all the facts, including those arising since the making of the order or decision, the commission is of the opinion that the original order or decision, or any part of it, is in any respect unjust or unwarranted or should be changed, the commission may abrogate, change or modify it and, if changed or modified, the modified order must be substituted in the place of the order originally entered and with like force and effect.