By contrast with the standard Windows Workflow Invoke Workflow Activity, which cannot easily be used with BlueIntegrator Workflows, the Call BlueIntegrator Workflow Activity invokes BlueIntegrator Workflows can be called synchronously or asynchronously, and in the former case can return values.  The Call BlueIntegrator Workflow Activity is configured via the Properties displayed in the Properties pane of the BlueIntegrator 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.