Join Date: Nov 2018
Location: Istanbul, Turkey
Programs: TK Elite Plus,BAEC GGL,ITA Executive, AFKL Gold,QR Gold,HH Diamond,Bonvoy Gold,ALL Gold
Posts: 14,186
No change fees are collected for all TK tickets booked until 31 March 2021.
For the moment, the semi-flexible/flexible thing is only different in terms of cancellation ( back to your credit card ).
All tickets could also be converted to an open ticket and be used at a future date.
You could see the cancellation penalties at the next step after choosing your flights. If it doesn't show up you would be a able to review them on the payment page before entering your credit card information.