For reserved seating events, the event capacity is set based on the number of seats on the seating chart. Any performance can have its capacity reduced, but it cannot exceed the event capacity.
To reduce the available seats for sale in a reserved seating event, you can block the seats from being purchased. Please follow this discussion for more information:
In the left menu, under Restrictions and Waitlist, check the EVENT CAPACITY. Click on the value shown to change it.
Click the checkmark to save.
The event's capacity -- if changed -- is the default performance capacity. Again, a performance's capacity can be reduced from the event's capacity, but it cannot exceed it. To change your performance capacity: