$ cat test_in.csv
id  name
123 john
34  john
567 john
11  peter
899 peter
87  helen
961 Anonymous Monk

##</code><code>##

$ cat -vet test_in.csv
id^Iname$
123^Ijohn$
34^Ijohn$
567^Ijohn$
11^Ipeter$
899^Ipeter$
87^Ihelen$
961^IAnonymous Monk$

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;
use autodie;
use constant NAME => 1;

my $infile = 'test_in.csv';
my $outfile = 'test_out.csv';

use Text::CSV;

my %seen;

{
    my $csv = Text::CSV::->new({
        binary => 1, sep_char => "\t", quote_char => undef,
    });
    open my $fh_in, '<:encoding(UTF-8)', $infile;
    open my $fh_out, '>:encoding(UTF-8)', $outfile;
    (undef) = scalar <$fh_in>; # skip & discard header record

    while (my $row = $csv->getline($fh_in)) {
        $csv->say($fh_out, $row) unless $seen{$row->[NAME]}++;
    }
}

##</code><code>##

$ cat test_out.csv
123 john
11  peter
87  helen
961 Anonymous Monk

##</code><code>##

$ cat -vet test_out.csv
123^Ijohn$
11^Ipeter$
87^Ihelen$
961^IAnonymous Monk$