If for any reason a (or several) booking(s) has/have to be canceled, you can delete it by marking it and 

  1. using the Delete button of your keyboard (for PC); for Mac, use Fn+back space
  2. use the Delete function appearing when right-clicking 
  3. or, by clicking on Delete  button at the bottom right of the Edit panel: 


If you need to delete several bookings in one go, mark them first using shift and apply any of the 3 methods above.