Listen to and manage your U-verse Voicemail messages by phone or online. Dial *98 from your U-verse home phone, dial your home phone number from another phone, or access your voicemail messages online from the Voicemail Settings tab. Press the * key when you hear your greeting. Enter your PIN. Press 4 and follow the prompts.
Note: If necessary, delete an existing greeting (limit of 2 greetings) to make room for the new greeting: Tap the Menu key, tap Delete greetings, tap the check box next to the desired greeting, and then tap Delete. Tap the Record icon to record your greeting. Tap the Stop recording icon to stop recording. Start by tapping on the phone icon found at your iPhone’s home screen. Go to the setting section on your iPhone. Now, you can go to the keypad on your phone and then type the number #404 and then call so that you are able to turn off voicemail on iPhone. How do you delete your voicemail greeting on iPhone? Tap Voicemail, then tap a message. Do any of the following: Play the message: Tap . Messages are saved until you delete them or your carrier erases them. Share the message: Tap . Delete the message: Tap . Why can’t I change my greeting on my iPhone?

source: I have had the same voicemail greeting for 6you years and would like to change it. how do i change my voicemail greeting on my droid x2? thanx?
Extension users can dial voicemail feature code (default *2) on their phones to access their voicemails. To enhance the extension security, you can change the voicemail PIN on PBX web interface.