/PREVALIDATE
       /NOPREVALIDATE (default)

    Prevalidate recipient addresses prior to invoking the editor
    to compose a message. If any illegal addresses are detected,
    PMDF MAIL will ask whether to cancel the operation or to proceed
    anyway. If told to proceed, both the good and bad addresses will
    appear in the editor where they may be modified as necessary.
    Validation will, of course, still be performed after the editor
    is exited.