By contrast with the standard Windows Workflow Invoke Workflow Activity, which cannot easily be used with Blue Integrator Workflows, the Call Blue Integrator Workflow Activity invokes Blue Integrator Workflows which can be called synchronously or asynchronously, and in the former case can return values. The Call Blue Integrator Workflow Activity is configured via the Properties displayed in the Properties pane of the Blue Integrator Workflow Designer.
The Workflow property drop down menu provides a list of available workflows to choose from. If you want the invoked workflow to change parameters passed use referenced parameters. If you require a return value, set the Synchronous property to True.