How do I change voicemail number?

I have a samsung eternity with att. I put the wrong center address number in and now I want to change it, how do I find that screen again? It used to come up when I pressed 1 but now I cant find how to change the number.How do I change voicemail number?tyr going to menu%26gt;%26gt;contacts%26gt;%26gt;speed dial and set whatever number as speed dial. I have verizon so I'm not sure if that's exactly right, but something along those lines.