I am afraid that is not possible in the Free or SMB version of 3CX. You will need a standalone version of 3CX to be able to do so.In Startup Free or SMB, and from an IP deskphone, how can I listen to another extension's voicemails, given I know the extension number and voicemail PIN for that extension?
Founded in 2005, when VoIP was an emerging technology, 3CX has gone on to establish itself as a global leader in business communications.