There's an internet site which i designed like a standard, static website with pages which i update as needed. All pages are *.html and that i possess some quite good google ratings.

I am presently re-penning this site to include a Content management systems in the after sales, this can either change all the pages to finish *.php in order to use routes (that is much more likely).

How do i alter the site but keep existing links and check results?

e.g. If I've got a connect to world wide web.mySite.com/myPage.html, but later on this is world wide web.mySite.com/myPage how do you do that having to break all links to myPage.html?

My hosting is Light right now, could this be carried out by changing the .htaccess file?

mod_rewrite should get the job done. You simply put something similar to this inside your .htaccess file

RewriteEngine on

RewriteBase /

RewriteRule ^(.*).html$ $1 [L,R=permanent]

This makes all demands to world wide web.example.com/yourpage.html to become rewritten to world wide web.example.com/yourpage. The R=permanent part leads to a permanent redirect answer be delivered to the customer, that ought to cause well-socialized search engines like google to update their records.