If an expense was in a status of awaiting approval when changes were made to the approval route, it will keep its original approval route. To re-route the expense so it picks up the new settings, the expense must be rejected and resubmitted. To reject it, an administrator or the incorrect approver can:
In the Approval screen, click the magnifying glass to find the person's approval queue.
Click their name and expand the expense in question.
Click Reject.