$data=~s/2000/2009/g;

##</code><code>##

my $new_array_ref;

foreach my $vals (@$array_ref)   # I'd use "$row" instead of "$vals", but whatever
{
    my ($acc_num,$date,$user1,$user2,$email,$user4,$user5,$user6,$country) = @$vals;

# do some edits that make sense... and then:

    push @$new_array_ref, [$date, $user1, $user2, ... ];
}