Buying a Home
If You Haven't Signed, Feel Free to Switch
Say you see a house for sale you are interested in, and you call the number on the sign in the front yard. The agent shows you the house, and you decide it's not right for you. Can you work with another agent when you look at other houses, or are you now "stuck"?
As long as you have not entered into some form of written agreement with an agent typically by signing a "buyer's agent" agreement you are not required nor even expected to contact that agent to look at other properties. Feel free to work with a variety of different agents when you're looking at houses. That way you can find an agent that meets your needs and that you enjoy working with.
But keep in mind that if an agent shows you a house, and you later purchase that home, the agent may be legally entitled to a commission from the seller of the home. So if an agent shows you a home, don't contact another agent if you decide to look at that home a second time. You'll only muddy the waters.