Originally Posted by
xliioper
You don't mention how far out your trip is. It's likely that significant schedule changes with MCT violations require some sort of manual review and the most likely explanation is that no one has reviewed the schedule change yet.
I don't see a 40 minutes connection in schedule until Sep 11th and later with 10:35AM arrival of VS454 and 11:15AM departure of DL2. Unless maybe you mean 30 minutes as it looks like DL had a schedule change where they dropped one of their flight frequencies on LHR-JFK (DL4) for most of Feb and Mar leaving only the morning DL2 flight.
OP stated they have a negative 40 min connection, meaning as an example, they arrive at 11:40 AM but their current connection to JFK departs at 11:00 AM.
But put simply, OP needs to contact DL to get it sorted out. DL can force open award space on its own flights. If OP is booked on TLV-LHR-JFK, DL could even rebook OP on a TLV-JFK nonstop if it's operating that day. Or DL could force open award space on a later DL operated LHR-JFK flight that meets MCT at LHR (providing OP's VS TLV-LHR flight arrives with enough connection time before the last flight of the day to JFK). Either option should be processed as an even exchange.