Library /sys$common/syshlp/mailhelp.hlb MAIL, Qualifiers, /EDIT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /EDIT
       /NOEDIT

    Invokes a text editor to edit the message you are sending. Unless
    you select a different editor, the DECTPU-based EVE editor
    is invoked. The /NOEDIT qualifier overrides the /EDIT default
    qualifier if you entered the DCL command MAIL/EDIT.

    You can use the /EDIT qualifier with the /LAST qualifier to edit
    the message before sending it.