By default voicemail is not active on telephones.
You are able to check to see if voicemail is on your extension through Outlook/OWA.
You are able to request voicemail activation through the Update telephone directory online form.
The light on the top right corner of the telephone display screen will flash.
While listening to a voicemail either:
You can force your voicemail PIN to be reset by trying to log in on a handset unsuccessfully 5 times (3 tries per call) and Exchange will send an email to you with a new PIN.
If the voicemail IS NOT on a shared extension or a PhD students phone you can also reset via Outlook.