At anytime you can change your password via your account panel. Once logged in, click on your profile name in the top right corner of the screen and choose "Edit profile". On the “Edit profile” page you can find a blue button named "Change your password", where you can change your password.
Please note that you need to enter your old password in order to change your password. If you do not remember the old password read the "I forgot my password" section on the Support page.