To change your security key's PIN or password:
- Open the "Settings" app of any Windows PC
- Click the "Accounts" box
- Go to "Sign-in Options" on the left-hand bar
- Click "Security Key" and go to "Manage"
- You will be asked to touch your security key. When done, you will be presented with the option to change your key's PIN or password. Click "Change," and enter your new PIN or password.