Your default max covers per time slot is 10 covers every 30mins, however, on special dates such as Christmas Eve, you would prefer this to be larger in the evening service so you can take advantage of larger party bookings for the festive season.
To change the max cover per time slot just for a date, you need to head to the override max covers per timeslot setting.
As you can see in the example below; we have changed the covers to be a max allowed of 20 per every time slot (which we have set to 30mins) but only over the allocated booking period of 17:00 - 22:00 to take advantage of the evening service.
See our quick overview video here about overriding default settings.