General Travel Informative - Making changes after booking thru an online travel service
There was an article in the travel section of the paper last weekend about making changes to dates for air travel. If you have purchased tickets through Travelocity, Orbitz or any online booking agency and you need to make a date change, contact the airline. Not only will it save you time but it will also save you from paying additional fees charged by the online agency.
Once a ticket is issued the online agency is no longer a party to the transaction. That explains why it can be next to impossible or take forever to make changes through them.