You can end an FTP session and return to the DCL prompt by
    entering the EXIT, quit, or bye commands or by pressing Ctrl/Z.
    The following examples close a connection with the remote host
    and exit FTP.

    FTP> EXIT
    221 Goodbye.
    $

    FTP> quit
    221 Goodbye.
    $

    To close a connection and remain at the FTP prompt, use the
    DISCONNECT or close command.