All you need to do is unpair the device in the Settings tab of your Monimoto app (app > settings > connect > unpair).
If by any chance you no longer have your phone and cannot unpair your device from the app, please contact our customer support and we will manually unpair it. Then you will only need to reset your device to default.
Setting the device to default:
MM1, MM2 - connect it to a computer (or just a charger) with batteries inserted for at least 13 seconds.
MM5, MM6 - press and hold the button next to the SIM card with batteries inserted for at least 3 seconds.
Monimoto 7 - press and hold the button on the backside of the device with batteries inserted for at least 7 seconds.
Now your Monimoto is ready for a new owner.