Expense report auditing process in detail manner

 Hi Folks,

I am new to iexpenses auditing process, 

I have created  expense report and submitted for approval

Approver approved the expense report.

Now AP user need to review before export into payables, and he found this information is not correct, how auditing process will restrict here since it is all ready approved. 

Also please explain how this functionality will help in real time business.

Note:- I have read full Internet expenses user and administration guide , still no clarity on this.