The Area being Modelled is :-
A Database for Lifecycle of a Sale

William Cody says :-   

Subject: Lifecycle data models

Question: I'm trying to model the lifecycle of a sale as it progresses through various stages like qualification,
getting a purchase offer, negotiation, and closing.

Each stage has explicit start & end events, approximate duration, and a set of activities that a salesperson would follow.

The key element to capture is the progression from one stage to the next.

Have you modelled that sort of process?

Thanks.