You'd use this method if you wanted to copy a listing that's already listed to list it as a different listing type (i.e. you have a sale listing that you want to list as a rental as well).
- Go to the Listing Record you want to Duplicate.
- Click More > Duplicate
- Choose what listing type you wish to use. For more info, see Listing Categories
- Select which Contacts you would like to copy
- Click Save