How to add post data into already exist array in Laravel

I have contact form. This is confrim page and final page that 'your message has been sent' message controller code.

I need to add couple of post data at 'confirm' page. How to recive those post data and add to '$data array' at complete function.

Could someone teach me way please.

/*
 * confirm page
 */
public function confirm(Request $request)
{
   $rules = [      
  ];
    $this->validate($request, $rules); 
    $data = $request->all(); 

    $request->session()->put('data',$data);
dd($request);
    return view('mail.confirm', compact("data"));
}

/*
 *　final page (your message has been sent page)
 */
public function complete(Request $request)
 { 
   $data = $request->session()->pull('data');
   $token = array_shift($data);
   $Contact = Contact::create($data);

    $data = session()->regenerateToken();
    return view('mail.complete');
}

via Chebli Mohamed