As a counter-example showing this not to be true, here is an SSCCE. Enjoy.

#!/usr/bin/perl -T
use strict;
use warnings;
use CGI::Lite ();

my $now = localtime (time ());
my $cgi = CGI::Lite->new;

# Retrieve existing cookies
my $cookies = $cgi->parse_cookies;
my $oldcookie = defined ($cookies) ? $cookies->{bigup401} : 'not set';

# Set new cookie
print "Set-Cookie: bigup401=$now\nContent-Type: text/html\n\n";

# Print the page
print <<EOT;
<p>Previous cookie value was $oldcookie<br />
New cookie value is $now</p>

<p><a href="$ENV{REQUEST_URI}">Get next one</a>.</p>
EOT
exit;
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thanks

have tried the above sample and working. but i wanted to replace exiting cookie name every time i open the page test.cgi. to replace the exiting cookie name. so its like replace exiting cookie on particular page when opened and closed