Laravel Auth - Redirect User to different url from function validator() after validation fails

I am trying to redirect user to different page after Unique validation fails

class RegisterController extends Controller
{
    use RegistersUsers;
    protected function validator(array $data){
        $validator = Validator::make($data, $rules, $messages);
        // If unique validation fails
        if($validator->fails()){ 
            $failed = $validator->failed();
            // if failed because unique mobile number validation rule
            return redirect('/somepage');
        }
     return $validator;
    }
}

when I try to do this, it give error

BadMethodCallException in RedirectResponse.php line 218:
Method [validate] does not exist on Redirect.

How can I redirect to some other page? am I missing something.

via Straw Hat