How to detect changes on client side

Hi,

I am using Webapi to get data and on the server side I am using EF5. The context is in the web project and POCO Entites are generated in a separate project("domain"). WPF application has a reference to "domain" project. As there is no tracking on the client side on the entities, how would I know which entities have been changed?. 

Thanks

Lee

http://leeontech.wordpress.com/