Join Date: Mar 2009
Location: NYC
Programs: AS MVPG, DL KM, Bee Six, Bonvoy Plat, Choice Plat, BW DS, Avis PC, Natl Exec, Greyhound Road Rewards
Posts: 19,992
On a prepaid reservation, there is a fee (I think it's like 50% or something) if you cancel or modify within a certain time frame.
On a pay-later (pay at counter) reservation, there's no fee to modify or cancel your reservation. If you don't cancel by the time of pick-up, you'll have to go to the counter or call reservations to have it canceled.
-J.