To change an existing approval route that is applied to a user please do the following:
Check the approval route of an example user who would be submitting a claim (Example expense route: Jane Doe)
Click Settings, Users
User the filter on the far right to find and select the user on the list
Click Actions, Edit
Check the approval route under Settings, Approval
Note down the name of this approval route.
Now you know their previous approval route find this in the approval list to configure
Click Settings, Approval
Find and select the relevant approval route
Click Actions, Edit
Change the title of this approval group (If named after the previous employee)
Change the Stage name and Approver in the relevant stages
Click Save. This will have now applied the configuration to each member already assigned to this approval route.
Note: An expense type level approval route would override a user level one