Yes, it is OK for you to represent the seller in this situation. However, you should make it clear to this new client that you cannot reveal to him any confidential information provided to you by your former client unless that client consents to the release of that information to the seller. While there may be little confidential information obtained from the buyer that would be of interest to the seller, it should be noted that information about material defects in the property is not considered confidential information under the Code of Ethics or the Real Estate License Act. Thus, if you had obtained material information about the property while representing your former buyer client, you would be required to disclose that information to the seller and any subsequent buyer of the property during your representation of the seller.
Source: TAR