I had a reservation on a NCL-BUD flight last August when Easyjet cancelled the flights because of a shortage of pilots. On the website I was only able to rebook onto the same route on different dates which was no use to me. I was able to change to a LTN-BUD flight by phoning Easyjet but spent over an hour on hold on an 0871 number which they had told me to call to rebook if I couldn't do it on the website.

I don't know if the mechanism of making changes is different when the change is initiated by you rather than a response to Easyjet cancelling the flight. However, if you have to phone them to transfer a booking the phone number is an 0905 number which costs 65 p/min and the administration fee per one-way flight changed is £20. Depending on the length of the phone call and the price paid for the original tickets, it may be cheaper simply to book new flights!