PURPOSE: To allow the system to improve the convenience for the subscriber without need of callback from the beginning to revise the arrival of a call to other subscriber and to relieve the processing load for an exchange.

CONSTITUTION: In a telephone network comprising plural exchanges adopting the common line signal system, when a called subscriber 23 does not reply a call or is busy, a caller exchange 10 receives lower 1-4 digits in a telephone number of a subscriber 24 whose destination is revised and sends the telephone number to a called exchange 20 in the common line signal system as a revision destination telephone number. The exchange 20 releases the connection to the called subscriber 23 and replaces the lower 1-4 digits of the received telephone number of the called subscriber 23 with the revised destination telephone number received from the exchange 10. The exchange 20 connects the called revised destination subscriber 24 and the caller subscriber 13.