A communication exchanging system comprising: an exchanger for forwarding a call for an user to a forwarding destination, said exchanger being adapted to automatically change the forwarding destination according to notification of a presence information of the user; and a terminal connected to said exchanger for notifying the presence information of the user; wherein said exchanger comprises: a presence receiving portion for receiving a presence information of the user from the terminal; a memory for memorizing a table in which forwarding destination information of the call for the user is registered so as to be classified by presence of the user; and a forwarding portion for retrieving the forwarding destination information from said table by the use of the presence information received by said presence receiving portion to forward the call to a forwarding destination represented by the forwarding destination information; and wherein said forwarding portion comprises a controller comprising an audio-text converting portion, a text-audio converting portion, an E-mail producing portion, and an instant message producing portion, and wherein said exchanger is adapted to allow designating a telephone number, an E-mail address and an instant message address as the forwarding destination, and to deal with a telephone call, E-mail and an instant message as the call, and to participate in an instant message service and monitor whether the user is logging in an instant message server (36, 45) to detect the presence information according to a monitoring result. an exchanger for forwarding a call for an user to a forwarding destination, said exchanger being adapted to automatically change the forwarding destination according to notification of a presence information of the user; and a terminal connected to said exchanger for notifying the presence information of the user; wherein said exchanger comprises: a presence receiving portion for receiving a presence information of the user from the terminal; a memory for memorizing a table in which forwarding destination information of the call for the user is registered so as to be classified by presence of the user; and a forwarding portion for retrieving the forwarding destination information from said table by the use of the presence information received by said presence receiving portion to forward the call to a forwarding destination represented by the forwarding destination information; and a presence receiving portion for receiving a presence information of the user from the terminal; a memory for memorizing a table in which forwarding destination information of the call for the user is registered so as to be classified by presence of the user; and a forwarding portion for retrieving the forwarding destination information from said table by the use of the presence information received by said presence receiving portion to forward the call to a forwarding destination represented by the forwarding destination information; and wherein said forwarding portion comprises a controller comprising an audio-text converting portion, a text-audio converting portion, an E-mail producing portion, and an instant message producing portion, and wherein said exchanger is adapted to allow designating a telephone number, an E-mail address and an instant message address as the forwarding destination, and to deal with a telephone call, E-mail and an instant message as the call, and to participate in an instant message service and monitor whether the user is logging in an instant message server (36, 45) to detect the presence information according to a monitoring result.