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. Navigate to your voicemail option if using a cell phone. … Listen to the recorded voicemail instructions. … Press the number on your keypad symbolizing “Yes” when asked if you want to delete your current message. … Select to record your own message if you want, or leave it as the mechanic default message. Step 1: Press # Right after you realize you want to delete your voicemail press the # symbol. It is VERY important that you do not hang up the phone. … Step 2: Listen to Menu. Once you press # on your phone, you will automatically be given access to a menu.
Tap Record a new greeting. 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.

When you set up Voicemail for iPhone 7, you can enter the Phone app, and then tap on "Voicemail" to access to Voicemail to change for the desired information.
Yea, same issue with me on Att network.. Frozen screen on voicemail settings. I was not even able to call myself to change the voicemail. I had to reset voicemail password over myatt app. And after that I was able to acess my voicemail over the phone. Still I cant change voicemail over the phone. Hope this will help you reset your voicemail.