This theme doesn’t affect the Search Functionality. If you’re having issues with it then it’s definitely something external as you can see it’s working fine on the demo – http://demo.appfinite.com/epik/?s=sample
It’s the Genesis Framework (Parent theme) and WordPress that gives you the default Search functionality. If you’re using a plugin and having issues, then you would need to either deactivate that plugin or contact the developers of that plugin to figure out what the issue may be.