* actions
|''begin transaction for client''| Joanna |''staff''| Bill|

|''begin transaction for client''| Bob|''staff''| Pual|

|''begin transaction for client''| Joe |''staff''| Bill|
 * checks
|''transactions pending''|
|''client''|''staff''|''owing''|
|Joanna|Bill|0.00|
|Bob|Pual|0.00|
|Joe |Bill|0.00|