There are a couple of ways of doing this, depending on whether you can remember your current password or not.
If you cannot remember the password at all, then you will need to click on the 'log on' button at the top right corner of the screen on our public page. Then just under the green login button, select the 'forgotten your password' button and follow the on screen instructions.
If you do know your current password and you just want to update or change it, then log on as normal and select the person in the top right corner. You will then be able to edit your password easily.