HOWEVER, the reason none of this matters is that there is no such thing as a binding purchase agreement against the BUYER. Offers are full of contingency periods during which buyers can always cancel. Plus the law gives Buyers additional rights to cancel depending when and even how some disclosures are delivered even if there are NO contingencies in the Offer itself.
Since you countered to an Offer I presume you are the Seller. The question becomes more complicated if you are now asking because the Buyer is trying to enforce terms of the expired Offer against YOU, which you are now trying to argue do not apply. As always, consult an attorney.
Best practice however is to add wording in the counter offer that specifies that the buyer by signing the counter offer extends the date of validity of its (original) offer to include the date of acceptance (or the date of the counter offer).
Michael HassanPour, Esq.
Coldwell Banker Beverly Hills North
Please, know that nothing is binding unless it is in writing and signed by both parties involved in the transaction. The accepted offer should include the terms in the agreement but If they have changed then I suggest that you confirm with the other party's agent.
Good luck to you!
Prudential Connecticut Realty
Prudential California Realty
Beverly Hill CA