How to easily change a graduate colour map into a choropleth with areas highlighted?

[DanPatterson]

What is your data?  You can easily change your classification type, so your question (in the title) isn't clear as to what you are trying to accomplish

[DengYijia]

How to make three regions of this map highlighted or make the rest of the map monochromatic (i.e. black and white) ?

[Robert_LeClair · Accepted solution]

One very easy way to do this is via a Definition Query on your layer.  Add a new field to your feature class and for the polygons to highlight, calculate the new field to 1 or "Yes" or whatever term you want.  Then switch your selection and calculate the other polygons to NOT show on the map as 2 or "No" or whatever term you want.

Then in the Layer Properties->Definition Query, perform a definition query where NewField = "Yes" and click OK.  Only those polygons meeting the query show.  Add the same layer to the map again below the first layer, perform a query where NewField = "No" and click OK.  Only those polygons meeting the query show.  Symbolize those layers and a clear outline for example.  I'm sure there's other ways of accomplishing the same task but this is the first that popped to my mind.