I thought TK charges a $70 fee to change an award flight, but I was apparently able to change it via their website for free?

I changed the date and departure city (destination remained IST, mileage cost was the same). The PNR hasn't changed. A bit concerned because I've gotten no email confirmation, but when I look at my account, it shows the updated flight. When I search for that flight again, I see the award availability is indeed no longer there. No charge to the credit card that I'd originally paid the taxes with.

Is this standard for TK, or should I perhaps call them and confirm the change?