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

       /EDIT
       /NOEDIT

    Invokes a text editor to edit the reply you are sending. Unless
    you have entered the SET EDITOR command, the DECTPU-based EVE
    editor is invoked. When you exit from the editor, Mail sends
    the edited message. To cancel sending the message, enter the
    command to quit. If you enter the DCL command MAIL/EDIT=(REPLY)
    and then decide that you do not want to invoke the editor for
    your response, enter the command ANSWER/NOEDIT.