Yes, you can.  Any changes to your booking can be made up to 48 hours prior to your scheduled booking.

To reschedule, or make changes to your booking, simply click on the “View / change booking” link found in your booking confirmation email.

The link is available  up to 48 hours prior to your scheduled booking time.

Bookings will not be rescheduled inside 48 hrs, to your scheduled booking time and no refunds will be provided.