When an appraisal is past the set Due Date and has not yet been marked as Complete, an Overdue badge will appear on the main appraisal list and on the details page for that order. 

To remove an Overdue badge from an appraisal, you must either change the Due Date to a later date, or set the file to Complete.

Here is how to see all orders in an Overdue status from your appraisal list. Click the Overdue icon towards the middle of your main appraisal filters list: