/sys$common/syshlp/helplib.hlb APPEND, Qualifiers, /NEW_VERSION  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /NEW_VERSION
       /NONEW_VERSION (default)

    Controls whether the APPEND command creates a new output file
    if the specified output file does not exist. (By default, the
    specified output file already exists.) If the specified output
    file does not already exist, use the /NEW_VERSION qualifier to
    create a new output file. If the output file does exist, the
    /NEW_VERSION qualifier is ignored and the input file is appended
    to the output file.