Unload/reload included class

Hi there, I trying to create CLI php application. It running continuously (server) and it will has a plugins. I want load, unload and reload plugins on the fly, without stop the application. Loading plugin is easy, when my app found new file in plugins dir, include and register it. But if i change the plugin source i must restart the app to reload it. Have anyone idea, how i can unload included (loaded) class? Thank you for every response. Best regards. Patrik Pomichal PHP developer Slovakia