If at any time the Mayor shall cease to possess any of the aforesaid qualifications of office or shall be convicted of a felony or other crime involving moral turpitude, it shall be the duty of Council to declare the office of Mayor vacant, and upon such declaration the office of Mayor shall automatically and immediately become vacant. Such declaration by Council shall be made only after public hearing upon the charge or charges brought and only if the Mayor shall have been notified in writing of the charge or charges against him or her at least fifteen (15) days in advance of such hearing, and only if the Mayor and his or her counsel shall have been given an opportunity to be heard, present evidence and examine, under oath, all witnesses appearing in support of such charge or charges. To be effective, such declaration of vacancy in the office of Mayor must receive the affirmative vote of two-thirds (2/3) of the membership of Council.