This is not favored in the industry! However, you can do this if you keep your contingencies in tact before rescinding from your offer without losing your initial deposit (typically 3% of purchase price).
Keller Williams Realty
Real Estate Agent
BRE Lic: #01941570
Offers themselves are not binding...also they certainly should be made with solid intent.
This is a strategy that you will find few agents willing to participate in. Yes, contracts can be written to give you ways out if more than one party accepts, but one element of making an offer is called Good Faith. That means you are serious in your intent to buy and are not wasting everyone's time.
While you see how this strategy may benefit you as a buyer, it hurts sellers and other buyers who are also pursuing purchases.
My advice is to find an outstanding agent who understands your goals, the current market and can help you get the home you really want.