From the home screen, swipe down the Notifications bar.
Tap the Settings icon.
Tap My device.
Tap Lock screen.
Tap Screen lock.
Touch and drag the saved pattern on the Pattern canvas. Note: You will automatically be sent to the next screen.
Touch and drag the new pattern on the Pattern canvas.
Touch and drag the new pattern on the Pattern canvas again.
Enter a backup PIN.
Re-enter the backup PIN.
After 5 wrong attempts, tap Forget pattern. Note: If the backup PIN is available, tap 'Backup PIN'. The device must have already been associated with a Google account for the Forgot Pattern option to display.
Enter your Google account login information, then tap Sign In.