In order to update your current password, make sure to find the Account Details section in "Me" category available in your admin panel (or click here).
To change the password, simply hit the "change password" button. Please note that you need to enter your password one last time before changing it to a new one.
In case you forgot your password and cannot even login to update it, don't hesitate to use the password recovery option available in the "sign in" menu:
You'll only need the email to recover access to your account.