HKG-TPE flight changed with no problem. Not the same flight but one slightly earlier (1hr 40m connection). Seats chosen on-line at CX website.So one day earlier in TPE with need to pay for an additional night there. The ba operator suggested that I call their customer care number. No urgency I guess.
The other problem is for me to source someone to stand-in for a radio programme I present and the associated logic of not being there. The flight had been planned for a specific day to save all that.
I'm happy enough that we are still flying!