PhoneSystemTransferCall(Int32, ActiveConnection, String) Method
request to transfer established call. (replace participant of the call)
In some very specific call scenarious it may be useful to set
dn to point to
ExternalLine participant of the call
In that case external participant of the call will be replaced with new one.
This method allows to replace participant even if both are bound to the same DN. For example if both praticipants are external and connected through the same line(trunk)