Section 41A. Any corporation having authorized shares without par value may, without increasing its capital, at a meeting duly called for the purpose, by vote of a majority of all its stock, or, if two or more classes of stock have been issued, of a majority of each class outstanding and entitled to vote, including in any event a majority of the outstanding stock of each class effected, change such shares or any class thereof into a greater number of shares without par value, or provide for the exchange thereof pro rata for a greater number of shares without par value; provided, that the preferences, voting powers, restrictions and qualifications of the outstanding shares so changed or exchanged shall not be otherwise impaired or diminished without the consent of the holders thereof.