The Board may amend, alter, suspend, discontinue, or terminate the Plan or any portion thereof at any time; provided , that no such amendment, alteration, suspension, discontinuation or termination shall be made without stockholder approval if such approval is necessary to comply with any regulatory requirement applicable to the Plan (including, without limitation, as necessary to comply with any rules or regulations of any securities exchange or inter-dealer quotation system on which the securities of the Company may be listed or quoted); provided , further , that any such amendment, alteration, suspension, discontinuance or termination that would materially and adversely affect the rights of any Participant or any holder or beneficiary of any Award theretofore granted shall not to that extent be effective without the consent of the affected Participant, holder or beneficiary. Notwithstanding the foregoing, no amendment shall be made to the last proviso of Section 13(b) without stockholder approval.