The certificate of incorporation of an authority may be amended to change or modify any provision or to add any provision which could have been included in the original certificate of incorporation. The amendment shall be effected in the following manner: The certificate of amendment shall be signed and acknowledged by each director before an officer authorized by the laws of the state to take acknowledgments of deeds and shall have attached thereto a certified copy of a resolution consenting to such amendment adopted by the authorizing subdivision or the authorizing subdivisions. Such certificate of amendment and certified copies of a resolution or resolutions shall be filed for record in the office of the judge of probate of the county in which the certificate of incorporation was filed. The judge of probate shall forthwith receive and record such certificate of amendment and attached documents. When such certificate of amendment and attached documents have been so filed, the amendment shall become effective as therein provided.