A special meeting may be called at any time by the presiding officer of a governing board or subboard, or by a majority of the members of the governing board or subboard, by delivering personally or by mail written notice to each member of the board or subboard, and to any medium or other party to be directly affected by a meeting, or any other person who has requested notice in writing. The call and notice of a special meeting shall be delivered at least 24 hours prior to any meeting and shall specify the time and place of the special meeting and the business to be transacted. No other business shall be considered at these meetings by the governing board or subboard. Written notice may be dispensed with as to any member who, at or prior to the time the meeting convenes, files with the clerk or the secretary of the governing board or subboard a written waiver of notice. The waiver may be given by telegram. Written notice may also be dispensed with as to any member who is actually present at the meeting at the time it convenes.