If you have a server that you keep private data on, but it is always on and internet connected, you might want to encrypt that data while you are away. The basic idea is to mount data as needed and unmount on timer or log-off.
There is an option --header <device or file storing the LUKS header> to use a detached (separated) metadata device or file where the LUKS header is stored. This options allows to store ciphertext and LUKS header on different devices. It means that we can have volume full of random crap without any determinate signature. Description of this option contains a bit more information, precautions and warnings, but the essential is just that. Yet I earnestly recommend you to read that fine
Assuming you have full access to the system and don’t have an ‘official’ way to remove it. Follow this to remove any full disk encryption software, even if you do not have keys to the full disk encryption software. You do need full admin rights and physical access.