BenQ M555C - Manual (Page 50)

34 Using your phone
Private
To talk privately with one participant during a multiparty call, press
to display the number of the caller you wish to talk to on the
screen, then select this option to put all the other callers on hold.
Exclude
Places one selected caller (whose number is currently displayed on
the screen) of a multiparty call on hold.
End current
During a multiparty call, you can end the call on one of the parties.
The currently displayed caller of a multiparty call can be
disconnected by selecting this option.
End all calls
Pressing , or selecting this option will end all the active and held
calls.
Transfer
This function allows you to end your own call and connect the active
and held calls, so the callers of the active and held calls can speak with
each other alone.