Hello.
Probably you are need to make the several reservations per the same date, so then you are need to check the Business Large version.
At the Booking Calendar Business Large version is possible to set the capacity of the booking resource, it’s mean that your visitors can make the several reservations per the same date, in other words, the date(s) in calendar will be available until lumber of reservations per these full dates is less than capacity of the booking resource. Please note, if you will use the timeslot selection for the booking resource with capacity higher than one, so then this timeslot will be simply record as a data into DB according this booking, but will not impact to the time availability.
Please read more info about the booking resources and how to configure them here
You can test Booking Calendar live demos at this page.
