How to load different templates

Hello I want to know that how can I load another template while remaining in a template. My scenario is as follow.
I have loaded a template by clicking on link (my module name) at admin panel navigation. Rendor() function of my class has rendered the template which I have specified. The class looks like


<?php
class mymodule_fconnect extends oxAdminView
{
    protected $_sThisTemplate = 'mymodule_fconnect.tpl';
    public function render()
    {
       parent::render();
       $oSmarty = oxUtilsView::getInstance()->getSmarty();
        $oSmarty->assign("oViewConf", $this->_aViewData["oViewConf"]);
        $oSmarty->assign("shop", $this->_aViewData["shop"]);
        return $this->_sThisTemplate;
    }
   function authenticate()
    {
        if ($data = oxConfig::getParameter("mymodule"))
        {
              // done some calculations and want to load the new template
                $mymodule_shopcreation = new mymodule_shopcreation();
                $mymodule_shopcreation->render();
                
        }
    }
}
?>

First my template is loaded then I submit a form to authenticate() function of this class and after doing some calculations I want to load the new template. My new class looks like.


<?php
class mymodule_shopcreation extends oxAdminView
{

    protected $_sThisTemplate = 'mymodule_shopcreation.tpl';
    public function render()
    {
        parent::render();
        
        $oSmarty = oxUtilsView::getInstance()->getSmarty();
        $oSmarty->assign("oViewConf", $this->_aViewData["oViewConf"]);
        $oSmarty->assign("shop", $this->_aViewData["shop"]);
        return $this->_sThisTemplate;
        
    }
}
?>

I have checked that control comes to rendor function of mymodule_shopcreation.tpl but template is not rendered.

What is wrong in my procedure? Is there another way to do the same task?

Waiting for quick response.
Regards,
Awais Qarni