Provisions of this Agreement may be amended and the observance thereof may be waived (either generally or in a particular instance and either retroactively or prospectively), only with the written consent of the Company and the Required Holders (or, in the case of an amendment to or wavier of the second sentence of Section 12 adversely affecting the rights of holders of Preferred Stock, the holders of two-thirds of the outstanding shares of Preferred Stock then outstanding). Any amendment or waiver effected in accordance with this Section 9 shall be binding upon the Purchaser and the Company. No such amendment shall be effective to the extent that it applies to less than all of the holders of the Registrable Securities.