I think you mean to transfer a call in progress similar to a call transfer used in a business system. The phone system controls the call path and by flashing the phone either by the button for that purpose or the xxx8220;switch hooksxxx8221; the called person gets dial tone and dials a number and hangs up once the party answers. This is not a feature on a cell phone but if the Blackberry MVS application is used by your business it may be something that would help, RIM has a Cisco application you might investigate.
Ixxx8217;m not sure of all the features.
KB17952-Managing call transferring on BlackBerry Mobile Voice System Console