Q. How do I leave a message for another extension user or transfer a call to their voicemail, without the phone ringing first?”
A. When calling another extension on your system, if you prefix the 3-digit extension number with 0 you’ll go straight to their voicemail. So if you need to transfer a caller to Steve’s voicemail on extension 123, for example, simply perform a transfer in the usual way but use 0123 instead of 123.
Similarly, this will also work with call forwarding rules and indeed anywhere else you can dial or specify a destination number.