Expanding on the simple approach above, let the caller know who they've reached. This will not only eliminate people leaving voicemails by mistake, but it will reassure the caller that they have called the number they intended.
From the Skype for Business desktop app (if you are running Click-2-Run build C2R 8201.1002 or later), select Set Up Voice Mail. Change your Call Answering Rules You can change what options your callers have when they reach the voicemail service; get disconnected, hear your greeting, record a message, choose to be transferred to the number or user you select. Change your prompt language This is the prompt language that is played to callers. For list of supported languages, see Languages for voicemail greetings and messages from Skype for Business. Configure your Out of Office greeting This is the customized greeting message that is played to callers when your status is Out of Office. This option can be activated "Always," when you have an active "Auto Reply" in Outlook, or whenever you have an out-of-office calendar appointment.  Where you can get your voicemail messages from

Business voicemail greetings are rarely thought of as a prime way to connect with customers. But just because you're not available doesn't mean you can't make a positive impression on your customers when they reach your voicemail box.
Domain = pepperdine (for non-students) Click on "Cisco Unity Assistant." On the main page, scroll down to the "Phone Password" fields. Enter a new 5-digit password in the "New Password" field; and re-enter it in the "Confirm New Password" field. Click the "Save" button at the bottom of the screen. Click the "Log Out" button on the upper right hand corner of the screen. Support