Far from free but there's a utility called AA Translator that can convert to and from Cool Edit and Audition to most of the other common DAWs. Obviously there are limitations since different DAWS have different capabilities but it works pretty well. Details here:
AATranslator - Home Page
Failing that, you could get the 28 day free trial of the current Audition and work quickly. Don't forget though that some versions back, .ses files were changed to XML .sesx files. There is a freeware (wll, contribution ware) that will convert ses to sesx.
Ses2sesx - Bulk Audition/CEP Conversion Utility