Any notice or request required or permitted under this Agreement shall be in writing and given or made by post-paid registered or certified mail, return receipt requested, or (b) personal delivery, facsimile, or express delivery service with acknowledgment of receipt, in either case, addressed to the Corporation at its then principal place of business, or to the Executive at his address specified on the first page hereof, or to either party hereto at such other address or addresses as such party may from time to time specify in a written notice given to the other party.