A subprocess (which is also an independent process) has its own EIId, which is specified by the parent process or updated later in the subprocess instance. The parent process should receive this value in any workstep prior to subprocess. The parent process can pass its EIId to the child process, if required, with proper mappings. For example, the parent process can pass the OrderId and ShipmentId to the subprocess, which can be used by the subprocess to identify the order to which this shipment belongs to.