How to make app for iPhone and iPad separatly

I released an app for iPhone (and it's could be downloaded for iPad also), and now I developered another app for iPad version with the same code and logic but I modified the layout to fit bigger screen and make better user experience and appearance.

Howevert the app review rejected my release due to the duplicate content, how can I solve it?

How to make app for iPhone and iPad separatly
 
 
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