A work flow to manage Epics in high level view of status transition. All status are reachable at any time, however advisable flow would be:

Request (anything that comes to mind..)

Analysis (requirement analysis)

Design (initial analysis approved - moving to more specific design from which sub-tasks or stories can be created)

Development (it's items are in development)

System Test (sub items developed but requires system test prior to being approved)

Impediment (halted, requires more info / additional actions)

Approved (tested and passed)

Deployed (released)

Could also be used for tests and tests or PRD oriented tasks