You can delete a device from the app by first selecting the desired smart lock and then clicking on "Settings".
Click on the "Delete" - button at the bottom. If you remove the device, you must confirm with your account password. Note that the device must be within bluetooth range and that the device is automatically reset.
Attention: If you have no longer access to your device (e.g. device is defect), you can delete it from the app like following:
Open the app and press at the top left of the main page. In the menu that opens, press "Settings". Now select "Transfer Lock" and select the desired lock. You can now delete the device by clicking on the button "Move damaged Locks to trash". Confirm with your account password.
Important: Only delete the device in this way if you no longer have access to the device.