If a prospect loses interest, you can mark them as a "Lost Prospect" in ResMan via Accounts > Prospects > Select "Prospect" > Leasing Workflow > Lost Prospect. This will take you to the "Lost Prospect" screen where you will provide a reason you lost that prospect.
Permissions and Settings
To mark a prospect lost you need permission to edit a prospect. To check permissions, go to Admin > User > (Select User) > Change Permissions > Prospects > Edit.