Change your ATT Email Password
1. Go to www.att.com
2. Type the Member ID in the User ID field.
3. Type the password for the Member ID in the Password field.
4. Click Log In
5. At the top of the page you will see an option profile Click on Profile option.
6. Scroll down to the Security Information section and click Edit Security Information.
7. Input your Current Password and New Passwords in the appropriate fields. You can also update your Security Questions.
And For More Information Call 1-877-827-1416 Toll Free
Reference:- AT&T Community Forums