3.1.4.3 Closing Handles
A handle of any type can be closed by calling LsarClose. Successful calls to LsarDeleteObject, which deletes an object to which the caller has an open handle, MUST also close the handle. The fact that a handle is closed is communicated to the RPC transport by returning a NULL value in the handle parameter, as specified in [C706] section 5.1.6.
Closing one handle MUST NOT affect any other handle on the server; that is, handles obtained using a policy handle MUST continue to be valid after that policy handle is closed.