Hello

I've an upcoming trip. It has two legs. Contact center says they can't change just one of the legs without repricing the whole thing. I want to change just one of these otherwise the asia-istanbul segment goes into C bucket.
They advised only a sales office could do it. They are not really picking up the phone and flight is tomorrow EOD.

Any clues as to what I should do other than try the luck at the airport tomorrow ?

Thanks !