I am assuming that you finally got ahold of Priceline and they were able to assist you? Please let me know. Thanks
Also I did find this information on Priceline, please read it as I believe it is something that relates to your question, add a ticket is changing yours as well. But there are also links in there that will drive you to the correct location to seek the information you seek if this does not answer your question.
Can I change or cancel my tickets?
The ability to change or cancel your airline tickets is dependent on the type of ticket you purchase.
Name Your Own Price® bookings, Express Deals, and any reservations where the full itinerary is not disclosed prior to purchase are non-refundable, non-changeable.
All other reservations are generally more flexible. Cancel and change rules vary by airline and fare purchased. The airline fares rules associated with your flight can be reviewed pre-purchase on your contract and post purchase within the itinerary displayed on our website.
If cancellations are permitted, a link to cancel may be available within your itinerary or you can call us to complete the cancellation for you.
If your fare rules allow a change and you are ready to exchange your reservation, please click here for additional guidance.