I called, because I never received a response after I replied to their first response from my form submission. Their email noted that I'm eligible for the change waiver, but "please note that your new travel should be completed by 31 March 2021, and a fare difference may apply if there is a change in destination or availability of a fare type." When I called to change the dates, my original fare code was still available, but they still wanted me to pay the fare difference since the difference was significantly higher. After 2 hours on the phone, they said they would open up an investigation even though they acknowledged what was said in the email. Not sure why the phone agents were not willing to follow the published policy. Hopefully their investigation will yield a positive result for me, because the fare code and routing is exactly the same.