You will need to pay a 100USD(?) reissue fee in addition to the additional miles charged. Just give asiamiles a call and they should be able to sort it out for you (provided that there are no married segment non-sense)

Just saying, you can also redeem a new ticket from KIX-HKG using asiamiles for 25k in J or 10k in Y. If you give them a call, they can put the new ticket in the same booking reference so all bags can be checked through, so depending your valuation of miles this is also possible.