Change Formatting Of Rows When Value Changes In Column

I have a spreadsheet where one column will determine the color of the entire row....if the sales persons name in column B = "Dew", the entire row should be shaded light blue. if the name is "Swiger" they should be white, when its Webb, it should be light blue again- alternatively, at every change in value in that column, alternate the entire rows shade - when the sales person name changes from Dew to Swiger, change the shading of Swigers Rows to white, when it changes from Swiger to Webb, make Webb's rows shaded the same blue as Dew's row's were....there are multiple rows for each sales person.