It is unfortunately not possible to simply exchange tickets. You can ask the organiser to refund your ticket and make a new order. Organiser contact details can be found under the event description or in your order confirmation email.
Remember to include the 7 or 8 digit Order IDs for all of your purchases (these can be found on your tickets and in the confirmation email), as these will help us or the organiser to process your refund faster.
NOTE: Your refund may take up to 21 working days to appear in your bank account. The booking fees and services are not refunded.