Hi Cc, Lisa has asked some good questions to help clarify just where you are in the process. If your offer was accepted by the seller, with both parties having signed off, and attorneys have blessed the documents (in New Jersey we have an attorney review period, often lasts around 3 days), then you are under contract and any new offers coming in should be viewed as back up offers which I would direct right to the seller's attorney.
If on the other hand, you submitted an offer on 6/08 and it was not accepted by the seller and you are not under contract, then you and the seller have no contractual obligation to notify or perform.
Clarify a bit and we can be more helpful.
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