(a) Any agreement which purports to waive, limit, disclaim, or in any way diminish the rights set forth in this article, except as provided pursuant to section four thousand nine hundred ten of this article shall be void as contrary to public policy.(b) Notwithstanding subsection (a) of this section, in lieu of the external appeal process as set forth in this article, a health care plan and a facility licensed pursuant to article twenty-eight of the public health law may agree to an alternative dispute resolution mechanism to resolve disputes otherwise subject to this article.