Originally Posted by SparseFlyer

There's an account code on your PNR that will automatically apply the 30% off whether the agent realizes it or not.

Your issue may be related to something else. You'll get an answer once we get the actual full picture (ie. give us all the details, not just the ones you think are relevant).

Originally Posted by King Chung Huang

You might be better off waiting until you've flown your outbound (after December 28), before changing the return flight.