How to deselect selected radio button option?

How I can reset a radio button field if the customer is changing some fields?

How a customer can reset his choice if he doesn't want to choose an option anymore?

With radio button, you can't toggle off the selected option once filled, unlike checkboxes. What you can do is to switch to another option instead, unless you reload the page which will clear all the field values.

Or use a drop down field instead. This has an empty option by default.