Input parameter in custom BO action

Hi,

From my understanding there is no way to pass parameters directly to an action of a custom BO but I read somewhere that a transient element can be used as a workaround. Just need a bit more info on how can I implement this.

Let's say there is an Input Field on a QA screen where user can enter some value a button that would trigger a BO action. How do I pass the value from the input filed to the transient element?

Thanks!

Paul