/sys$common/syshlp/helplib.hlb LIBRARY, /REPLACE, Example  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  $ LIBRARY/REPLACE/HELP HELPLIB NEWTEXT

      This LIBRARY command inserts into the help library HELPLIB.HLB
      the help modules from the file NEWTEXT.HLP. If a help module
      in NEWTEXT.HLP has the same name as an existing help module in
      the library, the module from NEWTEXT.HLP replaces the existing
      module.