You could probably re-ticket the fare and use the credit later (minus the change fee).

Did you mean cancel/credit the higher fare (less cancellation fee), and buy the sale fare?

Always an option, but the recent increase in cancellation fees means that the sale would need to at least be cheaper than the fees.

And some sale fares will have a reduced SP earn, and are not upgradable (F class) - both factors to consider.

What happens if one sector has now increased in cost while the other sector has reduced? Do both sectors need to be reticketed if indeed this was to be the chosen route?

because doing that would mitigate any benefit.

am mostly just interested in what is possible. Online reports suggest some airlines have a policy that allows fare difference to be refunded as credit but unsure if this depends on the time between booking and price dropping.

I have changed an economy fare to PE only for the return sector when there was a sale. Of course this is simply �buying up� the fare, and not quite what you seem to be asking about.

Typically re-ticketing involves re-pricing the entire journey.

And sale fares have complex rules and market specific availability. A sale fare AKL-SYD-AKL might not be available SYD-AKL-SYD.

DPS is becoming an bit like SIN/HKG, where it�s cheaper to fly through them than stop there.

Often you�ll see CX do say AKL-HKG-China mainline, for $100s less than than AKL-HKG.

Or when I booked AKL-SIN-HAN last week, it was $400 cheaper than just flying AKL-SIN on the same flight.

Yes. Very common to see this.

In 2016 I booked my son on TG AKL-BKK-NRT return.

48 hours in NRT and 3 weeks in BKK (which was the actual destination. $400-ish cheaper than a simple AKL-BKK return, and he had a �free� side trip to Japan.

How was he able to have a 3 week transit in BKK?

Ummm. He just entered Thailand on the (then) 30 day tourist visa.

From a fare construction point of view the destination was NRT and BKK was a transit in each direction. It was a multi-city journey, but there is still a 'destination'.
From a practical point of view, the routing was built so there was <48 hours in NRT and 3 weeks in BKK. Done this many, many times.

we searched CGK-AKL and air NZ ran this as CGK-DPS-AKL

As per above comments, it has been explained why it can be cheaper than DPS-AKL

are you saying we could stopover in DPS like your son stopped over for 3 weeks in BKK? Because I couldn�t see any option to stay 3 weeks in DPS?

Need to use a multi stop tool.

There is also the possibility that the underlying fare rules for the sale have time limits for stop overs.

As hinted at above. You need to try build what you want to achieve. If the online multi-city tool cannot cope, then a decent TA probably can. But it depends on digging deep if it gets tricky, and there can be annoying fare rules; for example some fare levels require a minimum number of nights at the 'destination' and/or have limitations on a 'stopover'.

The digging around yourself is (IMHO) vital to learning what is possible and how to achieve it

40love edited to add - see the example booking quickly constructed on the AirNZ site.
Note that this is $80 more expensive than a simple AKL-DPS-AKL, but hopefully this gives an example relevant to the general point.

Thanks Thai-Kiwi

I (wrongly?) assumed that if I booked multi-city with the dates like you used above, that I would be charged for 3 separate 1 way journeys?

Are you saying that in some scenarios, leg 2 and leg 3 would be charged the same/similarly to a leg 2 + leg 3 with no "stopover"?

By extension, if I am in Hong Kong and want to go to Jakarta, is there some way I can book a flight that goes through Singapore or Kuala Lumpur or Hanoi or Bangkok, and "stop over" for 2 weeks in that destination before flying on to Jakarta, and essentially pay the same as a HKG-CGK flight? (and if this IS the case, where should I start "digging around"?)

First & second questions - No, generally multi-city uses the furthest point as the 'destination', and so the pricing is on a return basis to that destination, sometimes cheaper or sometimes not. The intermediate sectors may also incur a fee if making a stopover. You need to think about the legs so that some legs are outbound, and some in the return return. And there might not even be a published fare if you get too tricky.

One the third question HKG-CGK with a long stop in BKK/KUL/HAN, this probably isn't available on an NZ fare, so getting off-thread. But certainly you can build that kind of journey - it may or may not be cheaper than just buying one-ways sectors. I have done so many times, mainly using airline websites, but also ITA matrix (a bit like using DOS), google flights (same engine as ITA matrix, but less customisable), skyscanner.net

See the THAI examples below

This is a multi-city construction


This is a one-way fare with a long connection in BKK. Note I can't quickly determine the exact fare class for this fare - THAI makes it tricky

The other benefit of utilising these types of fares is that they can really jack up the SP per dollar earn.

If I wanted to go AKL-SIN in J, at their current sale price this would cost $3,085 (one-way) and earn 178 SP, so $17.33/SP.

If I wanted to be savvy, I could, like the discussion upthread, go AKL-SIN-HAN with a long stop in SIN. This would cost me $2,721 one-way and earn 238 SP, so $11.43/SP - a 34% better value.

This tends to work out great for me as I travel to SIN and SEA regularly, and SIN is an allowable stopover for most (if not all) of Air NZ's marketed SEA destinations they do not fly directly to.

Now everybody will want to do this