Category - Home Selling Questions - General Home Selling FAQ's
This pertains to contingent offers when a seller has already accepted a contingent offer and another offer is presented that is non-contingent. If the seller wants to take the second non-contingent offer then they must notify the original buyers about the new offer. The buyer has only two choices…either remove their contingency or withdrawal their offer and look at other homes. The time the original buyers have to decide is usually 1-3 days thus the 24/48/72 hour clause. (This is also giving the buyer the right to first refusal.)
References
Courtesy of HomeOwners Advantage and link that to their entry in the wiki which is at HomeOwners Advantage