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That'd be a no. Special flight or no, the terms of carriage will apply and those will state you made a contract with Singapore Airlines to transfer you from point A to point B. There's nothing that says you should be on the same flight as originally promised. This is true for every airline. If you are delayed there might be some compensation but that's it. There's no special compensation for being delayed by re-routing compared to the flight just being late.
Although it was with Alaska Airlines and not with Singapore Airlines but last year I needed to be in Portland for a few hours and I had a flight booked leaving Vancouver at 11:50 am landing at 1pm and back the same day at 9:45 pm and I asked them what happens if the flight is delayed and the answer was essentially tough luck although it was painfully obvious from the ticket a significant delay makes the entire trip pointless.