Hi Psych, yep, understand completely - as there is now zero availability on those times / days.
I'll just leave it as-is, lesson learned - hoping to burn off some more of the Cx miles and will do better to take advantage of all angles. I think I was just intimidated to call - my first experience (2.5 years ago) was really slow going. Once COVID showed up, Cx tried repeatedly to reschedule me - I'm grateful - but each attempt was them calling me - and it was a slow and difficult to understand phone call, each time...always just to either "change flight or cancel reservation?"
So when it came time to call them - again - on purpose - I hesitated. But in the end, I had to call anyway - and it was entirely pleasant, fast, professional and understandable. I know that it's my own fault I don't speak Cantonese - but dog-gone, it was much - much - easier with someone that spoke English almost as good as I do.
Anyway - thanks for all the input, everyone. Great source of information here, I've said many times - continues to be true!