Aer Lingus changed Itinerary

Booked flights with Aer Lingus on Monday to Orlando for Sept. Received confirmation email. Today I received an email to say that the itinerary has changed. When I opened the mail it tells me that they have changed the flight to the following day and the same with the return flight. I would imagine they cover themselves for this under the terms and conditions, but do I have any come back at all? Is this normal? Am planning to ring them now to see what they say. Anyone had any similar experiences??

I would imagine you are entitled to a refund if the new itinerary does not suit, as it is they who changed it?