How to implement thin controllers?

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MVC

Hi , I am working on refactoring of a project. It is MVC project. Buisness logic is
scattered in 3 places -> Controllers, Decorator Classes and buisness operation classes.
Now I want to clean the controllers and write all the logic in single buisness operation class.
there I am facing problem, As I want to use controller only to give call to buisness operation methods
how should I write RedirectToAction or Return JsonResult in buisness operation class , as they can only be used in controlllers.