Are FLL-JFK and JFK-...-OAK in the same itinerary or two itineraries?
If two itineraries, I don't think you are entitled to a free re-route of both of them if only one of them had a schedule change.
If it is one itinerary, whoever wrote the ticket should reschedule it to something that works for you, at no extra charge, or refund your money.
What is the point of flying such a circuitous route as FLL-JFK-... OAK?
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