In some cases, you may need to add an ad hoc approver to the expense report approval chain. This will insert an extra approver in workflow for their review and approval of the request.
For efficiency, you should only use ad hoc approvals for one line in an expense report to avoid sending multiple notifications to the ad hoc approver. The ad hoc approver can then approve, deny, or pushback that one line. If the ad hoc approver believes multiple lines need to be pushed back or denied, that person will need to contact another approver in the expense report workflow, outside of the system, to stop the flow of the transaction.