The Board may amend, alter, suspend, discontinue, or terminate the Plan or any portion thereof at any time; provided , that (i) no amendment to Section 13(b) (to the extent required by the proviso in such Section 13(b)) shall be made without stockholder approval and (ii) no such amendment, alteration, suspension, discontinuation or termination shall be made without stockholder approval if such approval is necessary to comply with any tax or regulatory requirement applicable to the Plan (including, without limitation, as necessary to comply with any rules or requirements of any securities exchange or inter-dealer quotation system on which the shares of Common Stock 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.