Will Alaska automatically cancel duplicate award bookings made for the same day?🔥

Rather than asking whether it'll be automatically canceled, first think about how you plan to catch the second flight when the two are only an hour apart.

If both tickets involve mileage, it's best to proactively cancel the one you won't be using before departure rather than waiting for the system to handle it. Just make sure that, under the applicable rules, your miles and taxes will be refunded after cancellation—otherwise, the cost of saving that one ticket could be significant. Also leave yourself enough of a time buffer so that if the first flight is delayed, you don't end up losing out on both ends.

The post only says two SEA-LAX flights were booked—it doesn't mention whether they were on the same account or separate accounts, or whether they shared the same batch of miles. Clarify those two points first, then check them against AS's booking terms; that'll be more reliable than waiting for others' experiences.

An hour really is too tight—the system might not even have updated yet, and you'd miss your flight before you knew it.

Were both of these flights booked separately with miles under the same account, or is one of them under a companion's name? Also, did you receive a confirmation email after ticketing, and have the miles actually been deducted? These details determine whether this is a duplicate booking or two separate itineraries, which would lead to completely different discussions.

From a value perspective, keeping both segments could actually double your mileage usage and affect your future redemptions. What you really need to confirm is AS's official policy wording on same-day, same-route bookings—not just whether others have run into issues.

The key is still not to gamble on the system—proactively canceling the flight you won't take is the safest bet.