2. Press and hold the "1" key on the keypad. If it’s your first time setting up voicemail, you’ll likely see a message that says “No voicemail number is stored on the card.” If pressing this button dials your voicemail service, listen to the prompts for instructions on completing the setup process.
Android phones can access voicemail by holding down the 1 key on the dial pad until the phone dials your 10-digit phone number. You will automatically connect to your mailbox and be prompted to enter your temporary password; this password is the last 4 digits of your phone number followed by the # key. Start the Google Voice app. Tap the three horizontal lines at the top left of the screen (sometimes called a hamburger menu), and then tap “Settings.” In the Voicemail section, tap “Voicemail greeting.” Tap “Record a greeting.” How do I access my voicemail? To call your voicemail on an Android phone, simply open your phone’s dial pad and hold your finger down on the “1” key. You can also call your voicemail from a different phone by calling your own number and tapping the pound key. How do you check your voicemail?

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.
Call your home phone number. Depending on your location, you can press #, * or 2 to interrupt the greeting, and then enter your PIN. Follow the prompts to listen to your messages.