Pools
A Pool represents a participant — such as an organization, department, unit or role. Pools are often used to show collaboration between different entities or to distinguish between internal units of the same organization.
Each Pool contains a separate Process. For clarity, map only one coherent Process per Pool to create a clear visual boundary.
Pools can communicate with each other using Message Flows. However, you can’t use Sequence Flows, Data Associations, or Associations across Pool boundaries.
A diagram can contain only a single Process that exists outside any Pool.
Attributes
You’ll find Pool attributes and other settings within the Attributes panel, under the Attributes tab and other tabs.