Chiangi, it depends on what date is entered into the system by the reservation agent. That is why I said to make sure that it is far enough in the future not to have to go through that. But I found out the hard way that until ticketing is done, *any* change will cause the fare to go back to tariffs and be recalculated. In my case, it happened on my routing to DPS. CX has two flights a day, and I changed from the second to the first. Shouldn't (and didn't) change the base fare, but when it was sent to tariffs (without my knowing, even after I specifically asked them if it would be), I got a considerably less favorable exchange rate to the tune of about $200 more. I then ran into another problem with a res dropping out accidentally. I knew I was leaving at the end of June, and that it would be ticketed by then, so all the agents put the expiry date as July 1. When one of the agents made a change, she didn't put it as July 1, as any change to the record will reset the expiry to 24h. One day later, poof.

The ticketing of this trip was a comedy of errors, but it was like a comedy with Chevy Chase. A few laughs here and there, but generally it was just really painful to watch...