Originally Posted by Sannomiya

Thanks for your reply, yes, it is a I fare, bought for 4.8k CAD, or 3.8k or so USD, all booking attempts through the CX website.

Sorry for the mix-up, reason I asked is that at the time of booking, attempting to do so online in F would result in a 13k CAD fare, with indeed, the first leg in J instead of I, a huge upcharge for no benefits (that apply to me).

A dummy booking today for the same dates (8 months or so from now) resulted in 7.5k CAD D fare, or 19k (!) CAD J+F fare, while HKG-HND in F has remained around 5k USD.

So basically the question would have been better phrased as whether I could upcharge HKG-HND (preferrably one-way, but return if prices in the former are high) without touching the the YYZ-HKG leg at all (as I fare is good enough for me).