Ok so first thing to do when changing your password is to go into your profile and click on "Account Related Settings"
(http://i1299.photobucket.com/albums/ag69/Youshallfearme2/0392c3c4-f280-4b1b-a509-1c9aaa1d4754_zpsb5f5e7cd.jpg)
After that you go ahead and put in your new password in the box below.
(http://i1299.photobucket.com/albums/ag69/Youshallfearme2/5d5eb6e8-c567-4867-9041-272953863576_zps45b61f88.jpg)
Now you must still remember your old password in order for you to actually change it.