...
$name_hash{uc $username} = $password;
...
while(<STDIN>) {
    chomp;
    exit if $_ eq 'exit';
    my $name = uc $_;
    if (exists $name_hash{$name}) {
        print "The password for $name is $name_hash{$name}, please enter another name to search\n";
    } else {
        print "I'm sorry, there is no one here by that name, please try another name or type exit to end.\n";
    }
}