Booking a single segment, when joined segments are available
 

I'm looking at a trip later this year: NYC-CHC-HKG-NYC. When I search for just NYC-CHC-NYC, every flight I want is available, connecting through Hong Kong. When I look to separate the CHC-HKG and HKG-NYC legs, though (so that I can book a later HKG-NYC flight), the CHC-HKG flight is now showing as waitlist only.

If I call will they be able to book the CHC-HKG flight, given that it's clearly available if booked as part of a connection?

Classic Married Segment Control (MSC) problem. Availability is different depending on whether you have a connection or not (and where you are connecting to/from). In short, no, you will not get availability by calling in this case.

Bummer, since I really just want to add a few hours to the layover. I guess I can book now and just pay a change fee later. It's around the holidays so I don't really want the flight to get taken.

If within 24 hours it's considered a transit not a stopover. If the website is not displaying this option, you can call and try. If the website displays this option as not available, it is not available, but still doesn't hurt to call and just give it a try. Occasionally the website and the call centre see different things.

Thanks! It may be that it was just over 24 hours. I'll double check.

I redeemed a YYZ-HKG-TPE last year with AM after CX turned on Married Segment Control in Amedeus

Arriving HKG at 5am, online it restricted me to a 10am transit. By phone I delayed that all the way to 10pm.

I ended up getting a long layover on the way there (15 hours, arriving early AM, leaving late evening), which I guess is good enough. On the way back I'm going a more direct route which gets me two more days in NZ, so still a win. (Though I had to pay for that ticket.)

AM should really configure their website to allow all possible connections within 24 hours. This would save people having to call, more importantly having to staff up their call center to take calls like this that should rightfully be bookable online.

If you book revenue ticket as a multi city I think it will allow you to choose different connecting flights and if the transit is less than 24hours still charge you as if it’s a transit.

This has always been true in my experience, but the multi-city/stopover booking tool often seems to show fare codes as available even when they're not (most commonly for me, searching for E [and indeed I initially get it priced the same as the transit itineraries given by the main page booking tool or Google Flights or whatever], then get an unexplained error on the payment page, and the times I've called I've been told only R or W available). Main page booking tool doesn't seem to have that issue (er, in case you [reasonably] don't think this is a valid comparison, sometimes I use the multi-city/stopover booking tool just for my own amusement, even if unnecessary).