If you have to re-book have a look at Aer Lingus to MCO via DUB.
If it was cost effective you should consider the fact there is full US Immigration/Customs clearance at DUB.
I've used it several times since it was introduced in 2010 and it is great to arrive in the US as a domestic flight from DUB!
Incidentally US Immigration/Customs clearance is available at DUB for all airlines whose flights depart for the US before 1600hrs.