I didn't fill out a form. I called 1-800-325-2891 to find out what I had to do. I then sent my knife to Kershaw, 18600 SW Teton Avenue, Tualatin, Oregon 97062 with a note stating the problem.
I think it cost me around $3.00 to ship. I had the knife back in less than a month working fine. No charge for the repairs and shipped back on their nickle.
That's why I like Kershaw.