The most likely way to reset the phone lock of your LG Rumor Reflex is to flash in a new firmware. However if the phone lock is know, then the procedure is as follows
From the home screen, tap the HOME tab.
1. Tap Main Menu.
2. Scroll to and tap Settings.
3. Scroll to and tap Reset/Delete.
4. If prompted to Change Lock Code, tap the desired option.
5. Tap Reset Phone.
6. Tap Reset.
7. The handset will completely reset and then restart.