Fliegenmong
I was recently chatting with an ATC guy, who works in HK, and he did mention in passing, that a new ATC system that is due to go online in HK 'soon'?, is going to require a reduction in movements, from many carriers, perhaps in the order of 10%, and CX being the largest carrier by movements is going to have to cut more of its scheduled flights than other airlines, while HKCAD get it up and running.
I assume they are worried if the Cha lady accidentally pulls the plug out of the wall, to plug the vacuum cleaner in, that all the aircraft disappear into the black hole on the screen, less aircraft, smaller catastrophe.
I'm only guessing this could be the reason for the cancelled 157.