If a Case is no longer needed or has been created in error, you can delete it by going to the Actions Menu > Delete.
When you delete a Case all of its history is removed from Capsule. If you want to retain the Case history then you should Close the Case rather than delete it.
If a Case is deleted accidentally, you have 30 days to restore it before it is permanently deleted. The account Super Administrator can restore the Case from their Account Settings > Trash..