If the garage door opener has a keypad, change the code by erasing the old one from its memory and entering a new one into the pad. For garage door openers without keypads, change the code by changing the switches inside the remote and setting the ones on the opener unit to match. The slide switch technology without the keypad belongs to older openers.
Coding the unit with a keypad requires accessing the motor unit, so place a stepladder under it. Locate the learn switch on the motor unit, and press and hold it until it goes off, indicating the erasure of the old code. Press the learn button a second time, and enter the new code into the keypad. The indicator light should flash and then go dark, indicating the unit accepts the new code.
Activate the button on the motor a third time. When the light flashes this time, press the remote control to program it. Continue pushing the learn button and remote controls until you program all of them.
Reprogram the garage door opener any time you believe an unauthorized person has the code to the unit or if you lose a remote. Always reprogram openers with new installations and when moving into a new home.