Dealing with agents - ethics (newbie)

[Angela Kriv]

Hello! I am new to the field and need help with the following dilemma. I have a very nice lady real estate agent who helps me with the search. Also I dealt with her before and I like her. I came across a property on zillow that shows "sale by the owner". I send a message from zillow and the response came back from an agent. Now I am torn should I work with this new agent? I am a loyal person so I feel bad to work with another agent. Please, weathered REI, let me know is it ok in this line of business to work with many agents? What's the proper way?

PS. Also looking for any advise how to find an owner for a property if he / she is not responding?

Thanks everyone in advance!