If you are a new passenger who wants to change/cancel his or her Jetblue flight reservations then you can take the help of the simple FAQ available on the official website of the Jetblue Airlines that will help you with the easy cancelation and meanwhile, you can also apply for the flight change.
https://www.cheapflightinfo.com/travel/flight/what-does-it-cost-to-change-a-flight-on-jetblue