Help! I need my quick response team (QRT):

Wanted to change (on last years RTW, flying this Friday):

NRT-HKG 14th
HKG-ICN 14th

to

NRT-HKG 14th
HKG-ICN 15th (much less than 24 hours between flights)

CX Tokyo office says I "MIGHT" be slapped with a reissue because there was no stopover on the original ticket and they need to add/calculate airport tax.

So I say, "Ok, add the airport tax, but I am NOT stopping over. Since less than 24 hours I don't see a need to reissue ($75USD)".

So they say, well, we can't say......

Am I right, or completley wrong?

RDP

Many thanks as usual.