Originally Posted by
flyerCO
I believe that wording means you can upgrade flights on a ticket that has flights after expiration date of GUC. However only flights to be flown while the cert is valid can be upgraded.
That very well may be what Delta intends, but that's not what the terms and conditions literally say. Furthermore, it's demonstrably true that you
can upgrade flights that occur after a certificate expiration if they're confirmed and the ticket is reissued before the certificate expires.