You can call Orbitz and or Carnival directly....You should be able to at least get some onboard credit of some kind. Usually travel agents can handle this for you, but booking through ORbitz, you would have to find out....but yes, make some calls and good luck.
thanks everyone, I called but since I received a $200 onboard credit at the time I booked I would have to forfeit that to get a better cabin (that's all they offered since I am beyond final payment). I'll stick with what I have, six in one half dozen in the other
Carnival Liberty New Year's Eve 2007
Liberty of the Seas 5/2008+11/2009
Allure 1/16/ 2011
Vision OTS 2-14-2015
Freedom OTS 3/6/16