If you cancel a flight booked using a Delta SkyMiles American Express Companion Certificate in 2026, the outcome depends on the certificate's status. According to Delta's updated 2026 policy, if you cancel a "wholly unused" itinerary, the Companion Certificate is typically re-deposited into your SkyMiles account within a few business days. However, the certificate will retain its original expiration date; if that date has already passed, the certificate will be forfeited and cannot be used for a future booking. For the primary traveler's ticket, the fare is usually converted into a Delta eCredit (minus any applicable cancellation fees for Basic Economy tickets), while the taxes and fees paid for the companion are refunded to the original form of payment. It is important to note that you cannot "reuse" a certificate if you have already completed one leg of the journey (the "outbound" flight). To ensure the best chance of a successful re-deposit, most 2026 travelers are advised to cancel via the "My Trips" section of the Fly Delta app or by calling a representative if the certificate does not automatically reappear in their "Wallet."