If you have logged-in using your Facebook account, then you can change your password only through your Facebook account.
Steps to change your password on your soSAILize account:
1) On the main menu click "My Profile" button
2) From the drop-down menu select "Edit Details"
3) Find the Password fields and type your new password
4) Click "Save Changes" button.
That's it! Your new password has been saved!
This is how the "Edit Details" page almost looks like: