If you have a binding contract w/ buyer #1, you are required to meet the terms of that contract. Only if that contract is terminated in accordance with terms outlined can you move to a back up buyer without consequences.

If you have received, agreed on all terms and signed at the bottom line, the first buyer is your buyer unless something falls through during the inspection period.

You can take the second buyer as your back up offer.

A binding contract is a binding contract and you can't change your mind just because a better one comes along, just like you don't want your buyer to drop your house and make offer on another house just because it's cheaper.

Also, until everything is said and done, you really don't know if the second buyer is truly the better buyer - there still are a lot of negotiations and steps to be completed between now and close of escrow.

Sylvia