If you're using Apache, you can make it do an internal redirect by sending a Location header with an absolute (but local) path. For example:

package Foo;


use base 'CGI::Application';

sub setup {
        my $self = shift;
        $self->start_mode('mode1');
        $self->run_modes( mode1 => 'mode1' );
}

sub mode1 {
        my $self = shift;
        $self->header_add( -location => '/bar.pl?rm=mode2' );
}

1;
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