Please excuse my ignorance since I'm fairly new to the workflow process.

Here's the situation that we have:

Employee Enters PO
PO Goes to Supervisor for Approval
If successful it goes to Finance for Approval
PO Entered and everything is golden.


What I need to do is add a bit:
Employee Enters PO
PO Goes to Supervisor for Approval
If successful it goes to Finance for Approval
Then magically the employee realizes that he forgot to add a specific line to the PO
How do I restart the approval process?