|''begin transaction for client''| Joanna |''staff''| Bill|
|''return items''|3||coffee dispenser|
|''complete transaction''|

|''begin transaction for client''| Joanna |''staff''| Bill|
|''return items''|2||coffee dispenser|
|''complete transaction''|

|''rentals of client''|Joanna|
|''rental item''|

|''rental item subset''|
|''name''|''free count''|
|coffee dispenser|10|
