You must be logged in to be able to change your password. 

After changing your password, it may take up to an hour for the change to take effect.

If you change your password and are unable to log in, please wait an hour and try again.

If you are seeing "You may not update your username or password at this time. Please try again later." it means that you recently created your account, and it is still being processed. Once your new user account has been processed (typically within 24 hours), you will be able to change your password.