Just called AP to do a ticket change. Had a pre-deval PEK-BKK flight booked, and wanted to do a change to PEK-NRT. The original ticket was Asia 1-Asia 1, and the new change I'm wanting is also intra Asia 1. I had assumed I can change dates and destinations, as long as I stay within the zone for just the 90$ change fee, with no extra miles being charged. Agent wanted to top up to 80k. Whats right??