Step 1 - Click the Reset or Remove PIN and continue to the log in button

Step 2 - Click the forgot password link to receive a temporary password by email

Step 3 - Enter your email address and temporary password you received (type it in manually), then click on Remember my Details and set your PIN again. You can use the same PIN as before.  

If you always use a PIN and never log on to the website then there is no need to change the temporary password to a permanent one.