Revalidation

Revalidation is the process of updating or confirming an existing travel ticket or booking after a change has been made, without issuing a new ticket. 

It is most commonly used in air travel when details such as flight number, date, or time change, but the fare basis and ticket value remain the same. 

Instead of cancelling and reissuing the ticket, the airline revalidates it so the original ticket remains valid, even though it contains outdated itinerary information.

The purpose of revalidation is to keep the booking accurate while avoiding the complexity, fees, and accounting impact of a reissue. 

For example, the airline cancels the original flight and moves a passenger to another flight on the same day at a different time. Because the route and fare remain the same, the ticket is revalidated rather than reissued, allowing the traveler to use the original ticket.

Reissue, on the other hand, involves modifying an existing airline ticket to reflect changes in the itinerary or passenger details.