Before Covid hit for full and nearly all CX+ HKG transit stuff got canceled, I had several CX PNR's "amended" due to cancellations.

What they did is add the new segments as "extra" to the existing PNR, let me approve the changes and only then, ticket the correct ones and remove the obsolete ones. This made that the original segments did not disappear in limbo, just in case still needed (at the minimum for booking class). The difference might be, these changes were all due to CX changes in flight schedules and not my initiative (I kept flying throughout Covid, though "slightly" less, like being the only one in SQ business class, 3 pax in KE business class, etc, nice). In the end, nearly all my CX flights got canceled and only the early Covid CX flights went through.