Not that I buy too many full fares Empress, but that is what my understanding was, but I do not claim to be an expert at all in that area.

I have a current UA 'M' one way ticket LAX-SFO that I have changed the date of 3 times, with no problem at all, the last time being a few weeks back. I have also changed direction twice on it, same deal = done with no questions. 'M' is a high fare class coach fare, but not full Y of course, and it has caused no problem at all.

If I choose to cancel it I get a full refund tomorrow. It probably cost me 2 or 3 times a 'W' or 'T' fare. That I understood was the trade-off when I bought it ... lack of flexibility versus much higher cost?

Anyway, re the MX tickets, I am interested to learn if anyone ever asked MX or Orbitz if a date change was possible? I agree if that requires re-faring it is not a question I'd be asking. However, it *may* be Orbitz paid whatever MX wanted for these, and as far as MX is concerned they are flexible tickets. Who knows?