Change shape in a map chart

[Hundertjahr]

I'm creating a map of Minnesota, and the shape of 3 of the counties is wrong--they include sections of Lake Superior as part of the county (the purple section on the attached picture), which might be correct as far as legal jurisdictions, but I'd like my map to only include land mass. How do I change the shape of my counties?

 

[#2]

@Hundertjahr 

Afraid there is no way

[#3]

Thank you for your response. This is disappointing, as the mapping function was the main reason I upgraded Office, and now I'll have to develop some workaround. @Sergei Baklan