If you have purchased an auto-renewing lease, you can cancel the auto-renew subscription at any time and it will not auto-renew after the current paid lease period. Simply email [email protected] to let them know you wish to cancel. Make sure you email a few days before your lease auto-renews, so that there is time to cancel the lease before the auto-renewal goes through.
If you've purchased the 6 month lease, it does not auto-renew and will simply expire at the end of the 6 month period.
There are no refunds for any remaining time left on your lease. Your current lease will simply expire at the end of the current paid lease period.