1. To lock the device, press the Power button at the top of the device.
   
2. To unlock the device, press the Power button at the top of the device.
   
3. Swipe up from the lock screen and enter the password to unlock the device.
   
4. To change the password swipe from right to left at the edge of the screen to access the Action Center, then tap All settings.
   
5. Tap Accounts.
   
6. Tap Sign-in options.
   
7. Tap Change under Password.
   
8. Enter current password, new password, confirm password, then tap Next.
   
9. Tap Finish.
   Note: To learn more about requesting a device unlock for your AT&T mobile device, visit www.att.com/deviceunlock. If your device is locked and is requesting a "PUK" code, click here for instructions on how to obtain your PUK or PUK2 code to unlock your SIM card.