Pull the release rope and push the door all the way up until you hear a click. Re-engaging the garage door to the electric garage door unit. The door must be completely closed in order to re-connect the garage door opener to it correctly. Make sure the carriage unit is nearest to the garage door. In a power outage, all Chamberlain garage door openers can be opened using the red manual release cord. How to Disengage and Reengage your garage door opener if you need to open your door manually. If you have any other questions or need support, contact Chamberlain DIY Customer Service on 1800 665 438. An emergency release cord on the garage door arm opens the trolley to allow you to disengage the garage door from the opener. Note: Some garage doors do not have a manual lock once disengaged from the garage door opener. When power returns or it is safe to do so, re-engage the opener by pulling the red release cord down firmly. If your garage door has two different buttons that are used to open and close the garage door, simply click on the one that would typically close the door. After the garage door is closed, firmly press the garage door opener button.