CdWritted


function cf7_custom_form_url( $form_url ) {

global $post;

//The page id where the form is
$form_page_id = 18;

if ( $post->ID === $form_page_id ) {
return 'https://www.mywebsite.com/externalurl/';
}
else{
return $form_url;
}

}
add_filter( 'wpcf7_form_action_url', 'cf7_custom_form_url' );

You could send the form to a different url with POST and works it with php. Why not?