A personal voicemail greeting is an easy way to prevent callers from hearing a generic greeting message. It ensures that people know they've reached the correct person, and makes them feel more comfortable leaving a voicemail. To change your voicemail greeting on an iPhone, you'll need to follow a few simple steps.
For the users to be able to do this from the phone or by calling into the system the users will have to have pre-recorded greeting for different status and switch between them from the phone or by calling in to the system. They can do that from the web client, windows client or an android client.

For more accessibility options, see Learn how to navigate Skype for Business using accessible features.
To change your voicemail message on iPhone: 1. On your home screen, tap Phone. 2. At the bottom, tap Voicemail on the menu bar. 3. Tap Greeting in the top left corner of your screen. 4. Tap Custom if you want to record a custom greeting. 5. To record a new greeting, tap Record. Tap Play to listen to it. 6. Lastly, tap Save in the top right corner.