Any communication, notice or demand of any kind whatsoever which either party may be required or may desire to give to or serve upon the other shall be in writing and delivered by personal service (including express or courier service) or by registered or certified mail, postage prepaid, return receipt requested, at the addresses set forth above.  Any party may change its address for notice by written notice given to the other in the manner provided in this Section.  Any such communication, notice or demand shall be deemed to have been duly given or served on the date personally served, if by personal service, or on the date shown on the return receipt or other evidence of delivery, if mailed.