Originally Posted by
bgriff
You should have until 2359 Wednesday but be aware that the time zone of the departing flight is not necessarily the time zone in which the ticket was issued -- there have been some reports of a ticket issued by an office in SLC or elsewhere which, if that had happened in your case, would mean the effective purchase date was Monday, not Tuesday.
You used to be able to tell where the ticket was issued by notes in the receipt but of course Delta felt that was giving us too much power so stopped sharing that information.
This.
As others have reported, DL interprets "midnight" as the moment after 11:59:59 PM, rather than the moment before 12:00:01 AM. You do need to be aware of the time zone of the ticket.
I have on two occasions purchased a ticket midday for the following day, and then been able to cancel it just before the flight in question (ex: purchase at noon on Monday for flight 5pm Tuesday, successfully cancel at 3pm Tuesday).
I have not had the need to cancel the ticket after the actual flight, though.