I am redesigning a clients website that is ranking in google's first page or second page. His site is completely outdated so he wants a new design. I will be recreating the site with the same urls. I will also add a store to a subdomain and will input those links in the new design. So I will use all the file names and wordings that still exists. Can anyone let me know if there is anything I can do to prevent it from losing its ranking? It is html by the way. I will keep the same url and add additional urls pointing to an opencart site.