Relinquishing a Call
An application can relinquish ownership of a call by invoking 
lineSetCallPrivilege to change to a monitor application, or simply by using 
lineDeallocateCall to indicate that it has no further interest in the call. If the application
is the sole owner of the call and cannot hand off ownership to another
application, TAPI will not permit it to change to being a monitor or to deallocate its
call handle

in this situation, the application has no choice but to drop the call.
			
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