SDCL § 47-15-47: Method of giving notice--Waiver of notice.

If notice is required by chapters 47-15 to 47-20, inclusive, to be given to any person, the notice shall be given either personally, by mail, or electronic transmission. If mailed, the notice is given when deposited in the United States mail, with postage prepaid, addressed to the person's address as it appears on the records of the cooperative. If electronically transmitted, the notice is given when sent.

A signed waiver is equivalent to personal notice to the person so signing.