When a deal falls through, you will need to request Termination in reZEN. Learn more here: How do I Terminate a Transaction?
Your terminated deal will appear in your active transactions as "Termination Requested" until all required documents are uploaded and approved by the Broker. Once the Termination is approved, the status will change to "Terminated" and the deal will appear under the Terminated tab of "My Transactions" section in reZEN.