Is this form is going to be used to book a single holiday or to keep a record of a series of bookings?
If it is to be used for a single booking then you won't need much VBA. If you right click on a drop-down box and select Format Control you will see a Cell Link box on the Control tab. Put in the cell reference where you want the selection to be copied to. You wouldn't need a Book button then, either.
The easiest way to get your Cancel button to work is to record a macro to change the cells as you want.Then right click the button, select Assign Macro and assign the macro you've just recorded.
If the form is going to be used for a series of bookings we'll need a lot more information about how the sheet is laid out, the names of the drop downs (as shown in the Names box) and so on.