Polycom phone users have the option of transferring calls directly to another user's voicemail account.
This can be very useful for receptionists or PAs should the end user not want to take the call, but still wants the option of hearing the voicemail without being disturbed.
You can do this using the normal transferring method, but you precede the extension number by *55 (i.e. to transfer to the voicemail of 31200, you would transfer to *5531200).
More phone tips and tricks are found on the Polycom user guide.