Originally Posted by
the810
It is normally possible to have a segment booked into a lower booking class than the one fare requires, including lower cabins (AF sells a lot of J tickets with Y feeders on Jetstar for example, not to mention P tickets with feeders in J). But perhaps issuing this requires a higher level of competence from the agent.
Everything is possible and I don't think it's a question of competence of the agent. Here, we are talking about a change that is not part of the Ulti benefit which is a same-day free change of a flight providing there is still a seat available in the same class of travel. If OP would have asked for a voluntary change of his ticket, including a change of class, with full re-pricing, I'm sure it would have been possible. But certainly not at zero cost.