These by-laws may be altered, amended or repealed and new by-laws may be adopted by vote of two-third of the members of the board of directors then in office, present at any regular meeting or at any special meeting, provided that at least fifteen days’ written notice is given of the intention to alter, amend or repeal these by-laws or to adopt new by-laws at such meeting, provided further that the provisions of these by-laws with respect to members or directors may not be altered, amended or repealed, or new by-laws adopted, without the consent of a majority of the members or directors affected thereby.