A relevant but slightly different DP - I had an award booking OGG - HNL - JFK, and a scheduling change happened which reduced the layover time. They actually called to inform me of the schedule change, but the rep told me I couldn't change the OGG - HNL flight to be earlier since the change was only 1 hour difference, unless there was no fare difference. She offered to check fare difference for me but I was busy so I called them back later.
Next rep was more helpful and told me it's free to do a change so she helped me apply the change. I'm not sure whether this was because it was an award booking, it was the same booking # though.

The annoying thing with HA is their glitchy website and mobile app. They assigned our 2 seats (13A, 13B) for our OGG - HNL leg, but the seat shows both "13A,13B" on 1 passenger rather than per 13A and 13B for each corresponding passenger, and the seats aren't shown as selected in the UI even though in their system, they claim said the seats are confirmed for us. Whatever, not a big deal since it's such a short flight.

Another weird glitch was on our HNL - JFK leg, we had regular econ seats chosen, and when I went in to take a look at the seat options, it showed $0 to select Extra Comfort seats. So I selected them because why not, maybe it's actually free for some reason, and when selected in the UI, the seats looked confirmed. But when I asked the rep, they mentioned the seats for this leg was not confirmed, and that I'd have to pay the EC seat fees. I just switched back to the original seats, but felt catfished.