source: How do i delete my voicemail greeting on the pantech burst at&t and set it to the standard greeting the phone brings? angietraviss said: but if there is no option to delete greeting, just to change/rerecord Was this comment helpful? Yes | No jai87 Level 10 (Genius)
1. Call your number. It's that simple. Use any landline or cell phone to dial your mobile or landline number. Dial the full number. Make sure someone doesn't actually answer the phone you are calling when it rings, though. Make sure you dial the area code with the number.

If you’ve already created a custom voicemail on your iPhone, you can tap Play to see how your voicemail sounds. If you’re interested in creating a new message, tap the Custom button. From here, you can start recording your message by tapping Record and tapping Stop whenever you’re finished. Once you’re finished recording, tap on Play to make sure the message comes across as you’d like and hit Save (in the upper right) to save it as your voicemail.
Another worth considering trick is to remove all the old voicemails that are consuming the storage and creating multiple dilemmas like this. To delete the voicemail here are the steps, Open the Phone app. Tap on Voicemail at the bottom tab. Then tap on Edit at the top-right screen. Select All the Voicemails and at last tap Delete.