a conferencing method for a telephone switch system for performing a conferencing function . in addition to a simple conferencing function , if there is a call request from a new subscriber , a conferencing function subscriber makes the existing subscriber wait , and communicates with the new subscriber or selects to communicate with the existing subscriber . also , if it is desired to delete a specific subscriber , the specific subscriber can be deleted during conferencing communication , using a deletion key and a deletion code . if it is intended to delete some subscribers and add some subscriber during the conferencing communication , deletion and addition can be simultaneously performed , thereby achieving various conferencing services .