Abstract: A mail transmission/reception system, in which a user on the transmitting end, who wishes to revise or delete a print mail mistakenly sent to a remote user, can transmit a cancel mail to the destination address of the same remote user to have the specified print mail deleted on the remote user's computer system in S690, thereby preventing the print mail from being printed on the remote user's end. Also, the user on the transmitting end can know whether the printing has been prevented based on mail returned from the remote user in S660-S680 and can take appropriate measures when the mail cancellation has not been successful.