A communication method includes: transmitting a change request from a first conference server to a management server; determining that a second conference server is a conference server after change; transmitting an ID identifying the second conference server from the management server to the first conference server; transmitting a control request from the first conference server to the second conference server based on the ID; performing communication between the second conference server and the management server to confirm whether the second conference server is permitted to control the particular conference room; performing an initialization processing to control the particular conference room; transmitting a completion notification of initialization from the second conference server to the first conference server; transmitting a change instruction from the first conference server to each particular client; connecting each particular client with the second conference server; and disconnecting connection between each particular client and the first conference server.