Changing Home page page template of website weekly once, any affect from traffic of website, Pagerank and web promotion. How long regular interval of changing home page template?
It has nothing to do with SEO unless you change more than the template. E. g. if you use a template which shows the website name as H1 and change it to a template which shows the same text in another way, then it may have some impact on your position in search engines. However, it has nothing to do with pagerank. Pagerank depends on the links pointing to your website.
The changing on template or website layout won't effect on your seo unless the whole on-page factors have also been changed due to the change on template. If you mean about changing content frequently I would recommend you add a new unique content frequently instead. Too frequent change on the same content won't help you much, sometime could dilute your page important as well.