Scenario:
Usually, when a Project Leader approves an expense sheet, a record of the approval is saved in the project leader's Expense Approval History in his Web TimeSheet's Approvals section.
However; if the Administrator of Web TimeSheet reopens the expense sheet and makes modifications and approves it, then the Project Leader would no longer see the approved expense sheet in his expense approval history.

Note:
If the reopened expense sheet was submitted by the administrator instead of approving it directly, then it would again follow the approval process, waiting for the project leader to approve it once again. When approved by the project leader, it would show up in Expense Approval History?.