thanks everyone for chipping in.

i have, however, several examples of flights wherein i changed my return flight after having taken the outbound flight. when changing the "return" flight, as USFlyer said, there are constraints as to what can change. if it's the same origination and destination and the same stopovers then the new date and time can be repriced. often you can change the cities if you stay in the same countries (of departure and arrival) and i've also had luck changing the cities within the same continent.

in any case, the fact is that there is residual value and i am trying to learn what that is.


for those of you interested, my question stems from the fact that in the near future (10/18) LPs earned by flying on BA and IB will change to a spend basis. if buy a ticket today for 10/1 and return on 10/31 on BA, your LP will be calculated 2 different ways. we know well what the outbound LP will be but the return is a function of spend and that is why i'm trying to learn what the residual value is.

thanks!