How to call a page template in another page in php- Wordpress?

How to call a page template in another page in php- Wordpress?

OK. I have page template called "bannerpage.php". How do I call this page
so that the contents of this page are displayed on the homepage.php
I know that most common templates that have associated template tags
(i.e., , , , etc.), can be called but I don't know how to call a
"non-standard" template like bannerpage.php in Wordpress.
Any help would be much appreciated.