sub change {
    my $master = shift;
    my $entry  = shift;
    my $dn     = $entry->dn();
    (my $new = $dn) =~ s/\bou=Engineering\b/ou=Research/;
    my $err = $master->moddn( $entry, newrdn => $new );
    warn "could not update $dn: ", $err->text, ' (err=', $err->code,  ")\n" if $err->code > 0;
    $err->code > 0 ? 0 : 1;
}