Conditional Release because the realtor is only releasing you for sales made to parties that the realtor did not introduce you prior to signing the release -- ergo the "condition."
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what, exactly is your question?
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Attorney Corrigan is correct, but I would add that the best way to do this is to have an real estate attorney draft the release for you. A broker's commission is a big chunk of money and it's worth a few hundred dollars to get this right up front. I suggest it should be a general release with a carve out for a commission due only if you sell to a buyer the broker brought to you. What I would watch out for is situation arising after the release is signed where the broker sends a potential buyer your way and you sell to him and the broker wants a commission. So, be extremely clear with the carve out language that it only applies to a potential buyer the broker brought to you prior to the release being signed.