|''begin transaction for client''| Bob |''staff''| Bill |
|''rent''|1||Tricycle|''for''|1 day|
|'''ensure'''|''pay with credit card $''|20.00|''card type''|Visa|''expires''|11/05|''number''|4485891284549100|
|''complete transaction''|

|''begin transaction for client''| Bob |''staff''| Bill |
|''rent''|1||Bike|''for''|1 day|
|'''reject'''|''pay with credit card $''|200.00|''card type''|Visa|''expires''|12/05|''number''|49937395716|
|'''not'''|''complete transaction''|