(a) Except as otherwise provided in its articles of incorporation, a corporation may acquire its own shares. Unless the articles of incorporation prohibit their reissuance, shares so acquired shall constitute treasury shares.
(b) If the articles of incorporation prohibit the reissuance of acquired shares, the reacquisition of the shares shall effect a cancellation of them. A statement of cancellation as to the shares shall be filed as provided in Section 10A-2-6.32. The filing of a statement of cancellation with respect to the shares shall constitute an amendment to the corporation's articles of incorporation reducing the number of shares of the class of shares so canceled that the corporation is authorized to issue by the number of shares so canceled.