Mass. Gen. Laws ch. 156 § 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 affected, 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.
Mass. Gen. Laws ch. 156, § 41A