Pat, I realize that there is a language difference, but your question is very difficult to understand. If I am understanding it correctly, you were initially ticketed CMB-HKG-KIX with a transit in Hong Kong, and now you have to make a stop there. If you did not start your trip in Asia, it is no problem. If you did, then I cannot see Cathay penalizing you for something like this. There should be no difference in fare, and there is certainly no need for a reroute. If you have to pay the taxes, then you have to pay the taxes. If they tell you to, then I would talk to them and see if they will waive the tax fee, but unfortunately this is not Cathay charging you, it's Hong Kong charging you. But given how taxes are calculated and how the airport checks them, I don't think that the airport will say anything.

Dates on this fare are flexible. If you have to change the date to Colombo so that you do actually transit Hong Kong on the way to Sapporo, you should be able to.