Tried reaching out to TK on Twitter and that was worthless. They kept telling me they can't process changes and that ticket numbers begin with 235 even though I gave them the correct TK Booking Reference Number.

Then I called the number, went through the entire process, thought I was getting close, and the person says I need to contact my agency and add my email address (even though my email is already added to the ticket).

What an absolutely maddening process!! This was my first time booking TK and it's probably my last. Might even pay the Aeroplan cancellation fee to be done with it.