To enable persons trying to perform business such as a transaction to reserve a change of meeting each other and certify the performance of the reserved meeting.

The system has a site opened on a network 11 and terminals connected to the network 11. An item to be performed in a place to which a businessman or the like scheduled to go on a business trip is to be dispatched is transmitted from a terminal to the site and displayed on a web page 15 of the site, an offer to the item displayed on the web page 15 is transmitted from another terminal to the site and then transmitted to the terminal having transmitted the item, the self-authentification of reservation by the businessman or the like scheduled to go on the business trip is transmitted from the terminal to the site, and the offer is transmitted from the site to the terminal having transmitted the item.