You may find that when you partially refund a registration for a program, Altru will increase the event's availability.
The program availability is tied to the ticket (not the registrant) and Altru cancels the ticket when it is either fully or partially refunded.
If you are using a scheduled program, the ticket buyer's name will be removed from the Scheduled Event Ticket Detail Report. If you are using a program that requires registration, this will not cancel the registrant. You will need to go to your program event and mark the registrant as cancelled.