https://www.bangor.ac.uk/openday/change-or-cancel-booking
Change or Cancel Booking | Bangor University
change or cancel bookingbangor university
https://help.eurostar.com/faq/us-en/question/Can-I-cancel-or-change-a-non-refundable-hotel-booking
Can I cancel or change a non-refundable hotel booking? - Eurostar Help Centre
No. Changing the dates of your non-refundable booking is not possible.