SDCL § 47-21-58: Waiver of notice--Attendance as waiver--Exceptions.

Any person entitled to notice of a meeting may waive such notice in writing either before or after such meeting. If any such person shall attend such meeting, such attendance shall constitute a waiver of notice of such meeting, unless such person participates therein solely to object to the transaction of any business because the meeting has not been legally called or convened.