Delete the filled fields if they disappear

Hi, as you can see on the linked web page, I have a form that presents a select, depending on the user’s choice the rest of the form appears, the problem is that if a user selects the first choice of the select, but then changes and presses the second choice, the fields he initially filled in remain filled in, I would like them to be deleted automatically. I leave a link with a screen recording to help me understand better, thanks.

https://www.basenet.it/wp-content/uploads/2023/09/Registrazione-schermo-2023-09-26-alle-15.08.56.mov

The page I need help with: [log in to see the link]