// hook into wpcf7_before_send_mail
add_action( 'wpcf7_before_send_mail', function($contact_form){
// create new instance of WPCF7_Submission class
$submission = WPCF7_Submission::get_instance();
// email address you want to change
$toEmail = '[email protected]';
// set the email address to recipient
$mailProp = $contact_form->get_properties('mail');
$mailProp['mail']['recipient'] = $toEmail;
// update the form properties
$contact_form->set_properties(array('mail' => $mailProp['mail']));
});