Find "Change unlock pattern"
Press the menu icon.
Press Settings.
Press Location & security.
Press Change unlock pattern.
Change phone lock code
Press and drag a point to connect the points in the existing phone lock code.
Press and drag a point to connect at least four points to select a new phone lock code.
Press Continue.
Repeat the selected phone lock code to confirm.
Repeat the selected phone lock code to confirm.
Press Confirm.
Exit
Press and hold the Return key to return to standby mode.