Import expense report audit data from external system into Orace EBS iExpense

Hi Team,
In Oracle EBS R12 iExpenses, an expense report is created by the employee and sent for manager approval.
Post manager approval, expense report is sent for audit, to an external system, outside Oracle EBS R12.
In the external system, Auditor can short-pay the expense report by rejecting any expense line due to complaince etc.
This externally audited expense report is sent back to Oracle EBS E12.

Now, we want to import this audit data into Oracle EBS R12.
Please let us know if anyone has implemented similar requirement before.

Any pointers to achieve this solution will also be appreciated.