Hi, I thought I'd share my experience rebooking after flights changed from Q Suite to standard business class (twice).
When changes occur there are 2 different emails that get sent out, one with the subject "Changes to your QatarAirways flight timings" and one with subject "Important: A change in Business Class on your flight".
The "flight timings" email can mean there has been an equipment change but does not make Qatar support teams aware of this. We tried contacting QR by email, phone and twitter to arrange changes and they were able to help with small changes (date/time) due to the flexible booking policy, but not any route changes. The support team could not confirm Q Suite change at this point despite route/seat map information.
30 days before the flight that had changed from Q Suite departs we received the second email with the subject "Important: A change in Business Class on your flight" that states in the email that Q Suite is not available on the booked flight. In this instance when contacting support they can see the flight changes and help further.
After a long phone call we were able to change to a destination airport in a different country with no fees to pay. For reference we booked P class.