(1) In a multithreaded environment, to mark a thread so that the system reclaims the thread resources when the thread ends. If the thread is already ended, the resources are freed immediately.
(2) In cross-site mirroring, to disassociate a mirror copy from the production copy to use the mirror copy for a separate operation, such as to save data, to run reports, or to perform data mining. Detaching a mirror copy suspends geographic mirroring.