Hi,

I agree with Sandis, changing the extensions will definitely affect your ranking on Google. But since you want to add the advance search for which you need PHP, either you can do what Sandis has suggest, it’s a good way, but if your server does not allow you to do this then you can add new pages for Advanced Search and keep them as .php. Since these will be the new pages so there will not be any impact on the position of already existing pages.

Cheers,

~Maneet

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