That is what I have been doing. Logging on to the website, using the form shown in your screenshot, inputting the old password and a new password twice, and then clicking the Change Password button. I will try it again to see. Hold on.
OK, I just tried again. It does not work. Has anyone been able to change their password this way today. Usually I am not this obtuse, but something seems strange to me.
its not you, its the page. Its a mess, has always been a mess. Half the time i cant log in and i have also tried changing my passwords in the past multiple times and it do nothing. I would generally just wait a day and it would work.