Originally Posted by
JayPee
.....I thought IATA rules were that any change to the 1st coupon meant that the fare had to be that at the date of the change, which in this case would have been the 10% discounted fare.
That's correct. They should have been able to reissue the old ticket with date change, paying 5% fee, but less 10% discount, for a net savings of 5%.
From practical point of view, it is easier to refund the original ticket with 5% fee, then purchase a new one with 10% discount. Ticket reissueance can be very complicated and time consuming for long routings. It may also cause complications down the road if further changes become necessary.