Close Cases
When you reply to a customer with a definitive answer, you can change the case status to Closed by selecting Close in the Status field on the case record.
Closed cases are saved in your cases list, but by default, the list filters them out. You can view closed cases, but they're not visible with the open cases.
If a customer replies to the email message sent from the case, the case is re-opened, and is assigned to the last support rep who replied.
If the customer clicks Contact Support or an online case form link again, a new case is created, and the case workflow begins again.
If you use the Issue Management feature, cases can close automatically when all related issues are closed. For more information, see Setting Issue Management Preferences.