If you still remember your password
"User drop-down menu"> "Profile": go to the "PASSWORD" section, enter your current password and the new password in the designated fields. Click on "Change Password" to confirm this change.
If you can not remember your password
Log out ("User drop-down menu" / "Disconnect") then click on "Forgot your password?" and enter your email address. You will receive an email to reset your password. Follow the instructions.