You may reassign a mailbox to a customer if it is available after they resubscribe. However, it is not recommended to offer it for free. The system will automatically ask returning customers to retrieve their old mailbox for a fee that you have already set up. 

Please note: We don't identify customers (members) as renters since the relationship between operators and customers is membership-based not landlord/tenant, please ensure that this relationship is clearly represented to your customers.