dolfinco There is no automatic cooling off period for cancellation. Once you have completed payment of a reservation then there is no possibility to cancel and refund the reservation fully. Depending upon the fare rules for your reservation you may be able to cancel the reservation for a fee. You need to look at the fare rules for your reservation which are to be found as a link on one of the documents e-mailed to you in connection with your reservation.
Fare rules are almost unique to your reservation. They vary according to ticket class, origin, destination and sometimes date. They can also vary according to the sale offer you purchase. Often sale offers are non-refundable.