#!/usr/bin/perl

...

{ # scoping block
    my $rh_vars = {};

    if (...)
    {
        $rh_vars->{response} = 'whatever';

        if (...)
        {
            $rh_vars->{var2} = 'something';
        }

        func($rh_vars);
    }

    print $rh_vars->{response};
}

# $rh_vars out-of-scope here

...

exit 0;

sub func
{
    my $rh_vars = shift;

    if (exists $rh_vars->{var2})
    {
        # do something with "var2"
    }
}