The phone lock feature on your LG phone prevents unauthorized users from accessing your handset. If the phone doesn't have a clam shell design, it also prevents you from accidentally pressing any buttons while your LG phone is in your pocket or bag. As long as you know the current security password, you can create a new security password for your LG phone.
Turn on the LG phone. Press the "Menu" key.
Go to Settings>More>Security. Enter your old security password and press "Enter."
Select "Change Lock Code" and press "Enter."
Enter your new security password and press "Enter." Enter your new security password again to confirm it and press "Enter."
To set your LG phone lock, go to Settings>More>Security>Lock My Phone>Lock Now.
LG makes several series of phones and more than 50 handsets overall. Consult your LG phone user manual for more information about your specific phone model.