Looking for advice, hoping to maximize my chances of ending up with a happy story for this thread.
I asked twitter to apply an upgrade certificate to DL 1 LHR -> JFK on Dec 7. The certificate is applied and wait-listed, and looks not unpromising -- 5 unclaimed seats and at least 3 still for sale.
The tricky bit is that the certificate is set to expire on the 5th, two days before the flight. So should I try and 'get an extension', or hope for the best? My thought is that it could clear before it expires on the 5th, and that would be ok, or maybe the system says 'yep, there's a certificate applied so I'll use it regardless of expiration date'. Alternatively, when the certificate tries to clear, either before the 5th or after, the system will detect that the certificate is expired on day of travel and I'll be out of luck.