Library /sys$common/syshlp/ncphelp.hlb CLEAR, LOGGING, KNOWN_EVENTS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Indicates that the event filter is to be removed from the specified
 logging component or components.

 The KNOWN EVENTS parameter may be followed by a specific source for
 events (using the CIRCUIT,  LINE, or NODE parameters) or a specific
 location for logging these events (using the SINK parameter).  To
 remove events associated with a specific source or sink, the specific
 source or sink must be specified in the command.