You can log-on to your cloud-based account in the smart lock management software, anywhere with any device at, and remove access authorization/cancel your digital keys for your phone that is lost in seconds. When you delete the digital key in the lock management software, the unlock icon for that digital key will be instantly removed. When you get a new phone, simply download the Narrowband Digital Keys App and log in to your account and generate a new digital key in seconds. And the metal key still works. You can also use keycards, fobs, stickers to unlock the door too.