Just bought a C ticket on the Rapidair triangle which is a great deal or at least far cheaper than the regular J fare. Requires a 3 day advance booking and is reasonably flexible. Earlier this month I bought an L fare which was completely non changeable, even for a SE. No same day standby provision which really sucked. But on the C tkt, I was able to change my return from YYZ very easily. Bravo AC.