#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper qw(Dumper);

my $existing_users = {
    'user1' => {
	'UserName' => 'user1',
	'Ignore' => 'N',
	'LastAccessDate' => '0000-00-00'
    },
	    'user2' => {
		'UserName' => 'user2',
		'Ignore' => 'N',
		'LastAccessDate' => '0000-00-00'
	},
};

print Dumper send_to_sub($existing_users);

print Dumper send_to_sub_2(\%{$existing_users});

print Dumper send_to_sub_3(\%$existing_users);

sub send_to_sub {
    return @_;
}

sub send_to_sub_2 {
    return @_;
}

sub send_to_sub_3 {
    return @_;
}

__END__

$ perl test.pl
$VAR1 = {
          'user1' => {
                       'UserName' => 'user1',
                       'Ignore' => 'N',
                       'LastAccessDate' => '0000-00-00'
                     },
          'user2' => {
                       'UserName' => 'user2',
                       'LastAccessDate' => '0000-00-00',
                       'Ignore' => 'N'
                     }
        };
$VAR1 = {
          'user1' => {
                       'UserName' => 'user1',
                       'Ignore' => 'N',
                       'LastAccessDate' => '0000-00-00'
                     },
          'user2' => {
                       'UserName' => 'user2',
                       'LastAccessDate' => '0000-00-00',
                       'Ignore' => 'N'
                     }
        };
$VAR1 = {
          'user1' => {
                       'UserName' => 'user1',
                       'Ignore' => 'N',
                       'LastAccessDate' => '0000-00-00'
                     },
          'user2' => {
                       'UserName' => 'user2',
                       'LastAccessDate' => '0000-00-00',
                       'Ignore' => 'N'
                     }
        };