You can update your mailbox password at any time by following these steps ...
Log into Cloud Control at https://manage.cloudcontrol.net.au
Click the Mailboxes icon.
Click into the mailbox that needs its password changed.
Click the General tab, then enter your new password in the relevant fields.
Finally, click the Set Password button.
It may take a couple of minutes for the change to fully replicate through Active Directory, but in most cases, the change will be active immediately.