If the artist cancels their concert, you are entitled to a refund for your ticket from the organiser, or to a ticket for a new date. If the organiser offers an alternative artist instead, you are under no obligation to accept.

If an artist cancels their appearance at a festival, you cannot usually claim a refund. This is because when you buy a festival ticket, you are paying for access to the event as a whole, rather than for the performance of one specific artist. A single artist is not usually considered to be the most important part of the agreement. Furthermore, organisers often state that the line-up is subject to change. Therefore, if the festival still goes ahead, the agreement is, in principle, still considered to have been fulfilled.