An approver/admin can take additional actions on the report along with approving the report from their mobile app.
These include flagging, removing, commenting on an expense. To use these features on the app navigate to Team Reports > Click on Report > View All > Click on expense.
Once you click on an expense you can add/view comments for any further information, flag or remove this expense from the report
To remove or flag the expense you will be asked to fill the reason to do the same