I received the same email - I am flying LAX to EWR on Saturday morning and connecting to a flight to Rome that evening in business. My problem is this ticket was booked through Amex Platinum travel and is a codeshare ticket with Brussels Airlines. When I called United, they said I would have to call Amex if my flight is cancelled or delayed (which I understand) but that there is nothing I can do unless or until my current flights are cancelled or delayed.
Does that sound correct? There aren't a lot of business seats open on those Rome flights.
I guess I just wait and see?