Thanks. This worked for me also, once I figured out the "control box" is the inside door opener button. The LiftMaster has a pop off plate above the button. Inside is the red LED and a small button next to it. Entered the new code on the keypad and the LED lit up. Pressed the little button and the door began moving. Tested the old code to be sure it didn't work. Tested the other remote opener - it worked. Life is good.
Mahalo from Hawaii. Happy New Year!