Orbitz sucks for ticket changes. se Orbitz only if you want to book flights from multiple carriers and want to see the different options you have. Dont use Orbitz if you think you might have a ticket change later on. They don't do the ticket change properly. I won't book from Orbitz again.
I had a harrowing experience. I had my original flight from Boston to Los Angeled and called their customer service agent to change the flight. After speaking with them on the phone for 15 minutes, she sent me a new itinerary for my new destination which was Raleigh, NC.
However to my disgust, on the day of the flight when I reached the American Airlines counter in Boston, they told me that Orbitz had not changed my ticket properly and I was still booked for Los Angeles. After that I spent 45 minutes talking with multiple unresponsive Orbitz agents on the phone and each time it got cut off after around 10-15 mins. They probably realized that they were at fault and didn't have a solution and so cut the phone.
Then I talked to a nice agent at the AA booth and she changed my ticket for around 100$ since my new ticket was cheaper than the old ticket. I finally reached my destination 6 hrs after the original flight would have reached.
I would not recommend booking on Orbitz or any travel site. Check the available flights on these sites and then book your ticket at the airline itself. It is much better although it might take a little longer.