I want to migrate these pages with whole content from asta to Corporacy pro.

I am working on this website https://ccapitalplusauditing.ae Astra pro is used but it is not optimized for browsers and search engines. I want to change the theme to corporacy pro with all this content which is present on the website. My website is somehow ranked on some keywords on google and bing. I don't want to change the website's html structure. Is this possible?