You can transform an object of the Call activity type into an object of the Subprocess type. This transformation is allowed if the object is linked with connections other than the invokes connection.
Prerequisite
No diagram of the BPMN process diagram (BPMN 2.0) type is assigned to the object of the Call activity type.
Procedure
The object of the Call activity type is transformed into an object of the Subprocess type. This happens automatically for all occurrence copies of the object.