I have a mixed class Star Alliance award ticket booked through TAP Miles&Go: LPB-BOG-YUL on AV and AC. The first leg (LPB-BOG) is in economy since it was a single cabin aircraft when I booked, but the second leg (BOG-YUL) is business and I paid the miles for business. The first leg (LPB-BOG) now been changed to a two-cabin aircraft, and there are business class award available.
Can I call in to TAP Miles&Go to upgrade the economy seat to business on the same flight? Or will they charge a change fee?