This is one of the terms and conditions you agree to when purchasing theatre tickets. This is standard across the entire theatre ticket industry in the UK.
The only time where you will be offered a refund or exchange by the ticket vendor or theatre is if the performance has been cancelled. You will then be contacted by the company you purchased the tickets through and given the choice to either move your booking to another date, or obtain a full refund of all monies paid relating to the cancelled booking.
There is now hope however, as many ticket vendors are offering refund protection at a small extra cost. The extra cost is normally around £2.00 extra per ticket. You will then be protected if you need to cancel your booking due to a range of unexpected events including illness, accident or failure of transport. Make sure to read the fine print before confirming the extra protection so you are fully aware of the factors for obtaining and not obtaining a refund. Once purchasing the refund protection, you will be emailed a summary of the plan along with your ticket confirmation. In the unfortunate event that you need to request a refund, you must download a refund application form from the protection providers website and submit with any supporting documentation. You may be asked to provide the original unused tickets and other documentation such as doctors reports, official notices from transport providers if you journey was delayed or cancelled, police reports etc.
A full list of the ticket vendors terms and conditions will be freely available to you to read over before you confirm the booking. If you are buying in person from a ticket booth or theatre then they can provide you with a printed version, and if you are ordering online then there will be one or several prompts throughout the booking process where you can click the link to take you to the terms and conditions page.
Refunds are almost impossible to obtain if you have not purchased the refund protection however, exchanges can usually be done more often than not at the discretion of the ticket vendor. There is usually a small admin fee and requests must be made in writing. Exchanges are usually possible if the show is not completely sold out, if the performance you have booked is more than a couple of days in advance and if the vendor has not yet confirmed and paid for your tickets to the theatre. You will most likely be refused an exchange if you ask on the day of the performance as by this time, the tickets have been fully confirmed and paid for by the vendor.
If an exchange is not possible, then sometimes the vendor can offer to try and re-sell your tickets for you if you are unable to attend the show. This option is not the safest way as the vendor cannot guarantee that the tickets will be re-sold. If they are successfully re-sold then the amount will be credited to the card used when booking minus an admin fee.
Re-sales and exchanges are not standard policy and are offered only as a courtesy. No refund, no exchange
is the general rule when purchasing theatre tickets in London.