Sender Override for PS Expense Claims

Hi,

We have a requirement to override the sender of the automated email sent by the system whenever an employee submitted an expense report for review/approval.  Instead of the submitter's email address, they want a dummy email as the sender of the email. Can anyone point the location of code that sends the email?  I tried performing online trace but was not able to see that part that initialized the "From" field of the email.

Thanks in advance.

Regards,