Sorry if my posting upset some of you. It was merely meant to be a warning for the problem you can expect if you buy the ticket online.
While I agree that what you went through was incredibly frustrating - and it is somewhat ludicrous that a flexible ticket booked online can't simply be changed online - your advice ("Do not buy CX ticket online at Cathawy web site - ever") is a little over the top. The vast majority of people buying tickets do not or will not wish to make changes to those tickets once they have been purchased - so why should they not buy their tickets online, direct from CX?