During the candidate’s application process the candidate could have entered wrong information or could’ve possibly submitted a pre-interview vide with no audio. Regardless of the situation, you can move the candidate back to a specific phase/step in their process.
After going to the candidate’s profile, click on the current phase of the application he or she is on, located on the right-hand corner. Click on “Restart application” as indicated on the item (2):
As soon as you click on the “Restart” button a window will pop up with the option of phases you want your candidate to start over on: