In order to prevent your guests, from making a reservation on the desired date, you can use two solutions:
Solution 1:
1. In the calendar, add a reservation with a status of Unavailable.
2. If you plan to block availability in more rooms, copy this reservation to other rooms.
Solution 2:
1. Remove prices for the selected date in the BedBooking Price list.
2. No prices for a specific date, automatically blocks guests from booking.