An Expense administrator can change the approval route as follows.
Click Settings, then click Expense users.
Search for and click Actions.
Select Edit.
From here find out and take note of what Approval type they are on.
Go back to Settings, then click Approval.
Click the approval type, then click Actions.
Select Edit.
In this menu, the person's account should be linked under one of the Approvers, click the X to remove the user as an approver.
Type the name of the new approver, then click Save.
📌 Note: This will only apply to claims submitted after the change. Grant the new approver permission to approve on behalf of an existing group member to action outstanding claims.