Originally Posted by
EsherFlyer
Am I missing something, or should I be asking the TA to get me back onto the T+ fare even if they have to pay a further change fee
?
I would be asking your TA to fix it. You bought an S class ticket and you should remain in S class or higher, not downgrade to a lower fare class. If there is an ad-col for remaining in S class then the TA should advise you of this prior to just blindly changing the ticket. An S class and a K class ticket are not the same thing, especially now that AC treats K as Tango.