S.C. Code Ann. § 33-8-210: Action without meeting.

(a) Unless the articles of incorporation or bylaws provide otherwise, action required or permitted by Chapters 1 through 20 of this Title to be taken at a board of directors' meeting may be taken without a meeting if the action is assented to by all members of the board.

(b) The action may be evidenced by one or more written consents describing the action taken, signed by each director, and included in the minutes or filed with the corporate records reflecting the action taken. Action evidenced by written consents under this subsection is effective when the last director signs the consent, unless the consent specifies a different effective date. A consent signed under this subsection has the effect of a meeting vote and may be described as such in any document.