You can easily edit your booking from your dashboard.
Go to "List of bookings" on your left hand sidebar:
You can view all your bookings here by selecting the date range you'd like to view.
You can also search for a booking by booking reference, event name, vehicle plate etc.
Once you've found the booking you'd like to edit, select it and the option to edit will be in the upper right hand corner in a green box.
You will receive email notification on all the changes you make.
You can now go through your booking, making any changes you need.