Originally Posted by
emcampbe
i always understood that if same fare bucket is available, there is no fare difference. At least that’s the way it has always been for regular changes - if there’s inventory in same fare bucket, than no fare difference, if you need to go up a fare bucket, then you do pay the difference.
UA’s rules specifically call out the possibility for a non-premier member to pay a fare difference even if there is inventory in the same bucket.
As near as I can figure, that would imply one of these things:
(a) SDCs will use current fares, not historical fares, but ignore advance purchase / use the original purchase date; if the G fare has changed amounts, you’d have to pay the difference. (And if a G fare is no longer filed, you’d have to upfare)
(b) SDCs use historical fares but do not ignore advance purchase rules, so if there was a 7-day AP and 0-day AP fare in the same bucket, and you originally booked the former, you’d have to pay the difference.
(c) SDCs use current fares and enforce advance purchase rules, in which case it’s just the walk up fare and SDC provides no benefit at all.
Note that if you expect to change a return flight, there may be an advantage to buying a round-trip ticket even if there is no fare savings, because you’ll normally get rule (a) automatically for all changes to the return segment.