Currently Cashman Casino mobile is designed to be in use for a single user account. This means that once signed in, your Facebook account will be locked into the device. The only way you can permanently log out of the application is to do a full factory reset on your iOS device.
Uninstalling and reinstalling the app will log your Facebook account out, but it will not allow you to connect a second Facebook account. The device will only allow the original Facebook account to sign in.
We apologize for any inconvenience this may have caused you.
WARNING: Performing a factory reset of your device and erasing all content and settings will delete all of the data from your device. This includes songs, videos, contacts, photos, calendar information, and everything else. All device settings are restored to their factory condition.
If you still wish to do this, you can follow Apple's instructions here: