S.D. Codified Laws § 47-23-6
Any action required by chapters 47-22 to 47-28, inclusive, to be taken at a meeting of the members or directors of a corporation, or any action which may be taken at a meeting of the members or directors or of a committee of directors, may be taken without a meeting if a consent in writing, setting forth the action so taken, shall be signed by all the members entitled to vote with respect to the subject matter thereof, or all of the directors, or all of the members of the committee of directors, as the case may be. If permitted in the articles of incorporation or the bylaws, such consent and signature may be transmitted by any reasonable means including, but not limited to, traditional mail, hand delivery, email, or electronic facsimile.
Such consent shall have the same force and effect as a unanimous vote, and may be stated as such in any articles or document filed with the secretary of state under chapters 47-22 to 47-28, inclusive.
SDCL 47-23-6