Karen,
Back in the good old days airlines would overlook something like this, but with things being the way they are now with air travel agents can lose their jobs for making small mistakes like this. I would call the airline up and give them your confirmation # and find out first hand if it warrants making the change. They will be more than happy to assist you and plus you'll hear from the horses mouth. I'm assuming expedia have tagged on their fees and the carrier might make the change for you for less.
Hope that helps.
Happy Holidays - Cheers - Ian Pinto