Rebooking ticket question, regarding ticket class
 

As a DL Platinum, I booked a ticket on NW in Q class. I ended up not taking the flight due to a work reschedule. I am trying to use the ticket value towards a new ticket. However, I was told by an agent on the phone that I must purchase a Q class or higher class ticket. I have never seen this in any other airline.

After reading through the fare rules, I still do not see this limitation. Can anyone help give me some information on this?

To help, here are the fare rules: http://www.nwa.com/cgi-bin/view_fare...howidx=0&ref=2

Is it a domestic ticket or international?

On a domestic ticket you will need to pay the additional fare, if there is any, administrative change fee and perhaps a call center assistance fee.

On an International ticket you must purchase the same fare or higher subject to addl fare and admin fee and the call center assistance fee.

Domestic.

I know I would need to pay any additional fare, I am good with that. But since I am trying to buy different routing tickets with the credit, do I actually need to book the same fare class or higher?

NO any fare would work.