If both you and your friend will be using the same ZUS, you may add your friend to your ZUS via Family Share. Then both you and your friend can use the same device and you would know where and when your friend parked. You would still be the owner.
If you will not be using this ZUS anymore, you will need to remove this ZUS from your ZUS app before giving it to someone else. Then he/she can pair with it and use it as the owner.