S.C. Code Ann. § 7-11-53

If the executive committee of a political party substitutes a candidate for a general or special election pursuant to Section 7-11-50, it must do so as soon as is reasonably possible. The executive committee must nominate a substitute candidate for an office not more than thirty days from the date the candidacy becomes vacant. If a party fails to name a substitute candidate within thirty days pursuant to Section 7-11-50, that party is prohibited from nominating a candidate for that office.