Library /sys$common/syshlp/mailhelp.hlb SET-SHOW, PERSONAL_NAME, Parameter  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 "text-string"

    Specifies the string following your node name and user name for
    the From: field of mail messages you send. You must enclose
    the string in quotation marks; otherwise, Mail converts it to
    uppercase letters. You must begin the string with an alphabetic
    character and avoid two consecutive embedded spaces within the
    string. The length of the text string should not exceed 127
    characters.