public function UnInvite($InvitationID = '', $TransientKey = '') {
      $this->Permission('Garden.SignIn.Allow');
      $InvitationModel = new InvitationModel();
      $Session = Gdn::Session();
      if ($Session->ValidateTransientKey($TransientKey)) {
         try {
            $InvitationModel->Delete($InvitationID, $this->UserModel);
         } catch (Exception $ex) {
            $this->Form->AddError(strip_tags($ex->getMessage()));
         }
            
         if ($this->Form->ErrorCount() == 0)
            $this->InformMessage(T('The invitation was removed successfully.'));

      }
      
      $this->View = 'Invitations';
      $this->Invitations();
   }