VMS Help EXCHANGE, HELP, Parameters  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 command

    Specifies the name of the EXCHANGE command that you want
    information about. If you omit the command, HELP displays general
    information listing all commands recognized by EXCHANGE.

 qualifier

    Gives the name of the qualifier to be explained.

 option

    Gives the name of the option to be explained.