How to re-enqueue the script I deregister on event+?

So after I enable Event+ Next Cal widget, it out put this script on every single page on my website. But only 1 page of my site use this widget. So I want to globally deregister this script in my functions.php like this:

wp_deregister_script( 'eab-upcoming_calendar_widget-script' );

But then, on this condition:

if (is_page_template('page-atvgroup.php')) 

I want to enquene the script back...But I can not figure it how...How can I point back to the plug-in dir for the script? Which filter/action I hook back in to make sure this enquene happen after the deregister? What is the php code?