Removing Cart items

On the booking form once customer completes the booking fomr on a tour and clicks Booking Now button, it takes you to the check out page with Paypal on the right side https://www.phuketdreamcompany.asia/tours/a-day-trip-white-water-rafting-elephant-trekking-flying-fox

How can customers edit cart items? There is no My cart button or edit cart in that Paypal screen item list