How do I change the AT&T app from opening when I unlock my phone?

[AC Question]

When I unlock my phone to text, for instance or to see a text that someone sent, I have to close the AT&T screen before I can see messaging. I don't want that to be the default. I would rather have the home screen with my wall paper and then tap the message icon from the bottom. So when you are texting someone, every time I have to switch from AT&T to messaging. Most annoying. Please help!