Totally. The basic process is:
1. Create a calculated field using and IF/THEN statement to return one value for the special case, and a second value for everything else. To make life easier, typically these are plain-English (or language of your choice) values.
2. Put that calculated field on the Color shelf. The values then become labels for the different colors.
The specifics of step #1 are very dependent on how your data is organized and what kind of change you are trying to highlight, so posting a workbook with sample data would be helpful to give a more exact answer.