Hello Doassuepoi93
What kind of ticket do you have? If this ticket is refundable, it would be easier to cancel it and buy a new one in 1st class.
If the ticket is not refundable, I don’t know if it is possible, perhaps in Switzerland, but probably not in Austria. It depends of the conditions, you should ask the seller directly. International tariffs are not published and we cannot check these conditions to help you.
Kind regards
Danhiel