Del. Code tit. 3 § 8512
The articles of association may be amended pursuant to an affirmative vote of two-thirds of all the common stockholders or the members of a representative body or council in attendance at any regular meeting, or at a special meeting called for the purpose, due notice of the time, place and object of which regular or special meeting has been given as prescribed in the bylaws. A copy of such amendment, signed and acknowledged by not less than 3 of the directors, shall be presented to the Secretary of State, who shall examine the same, and, if he or she finds it in proper form, shall endorse approval thereon. The amendment shall then be filed in the office of the Secretary of State. A certified copy of the amendment, together with the endorsements thereon, shall then be recorded in the office of the recorder of deeds in the county where the principal place of business is situated.
3 Del. C. § 8512