Use case diagram - primary and secondary actor at the same time

Question

Can an actor be both primary and secondary in an extended management system?

e.g. Warehouse worker [use case] displays the list of orders to be packed (as secondary actor), then [use cases] packs the order, marks the order as ready (as primary actor)

Answer 1

Yes, an actor can be both primary and secondary in the same diagram:

• The qualification “primary” vs “secondary” is use-case per use-case: A use-case expresses an actor goal. The primary actor is the one who has such a goal. Secondary actors are any other actors involved in the use case to help achieving the goal of the primary actor.
• Occasionally, "primary" and "secondary" for the system as a whole system, but with a slightly different meaning: primary actors are then those for whom the system is made.
• UML does not define nor even use the terminology of “primary” and “secondary” actors. Moreover, UML leaves the semantics of multiple actors for a same use-case unspecified.
• By the way the use-case community tends nowadays to prefer the term of “supporting actor” rather than “secondary actor”. (Secondary sounds as if they were less important or even optional, whereas supporting suggests better that these are as important as the primary actor).