https://userapps.support.sap.com/sap/support/knowledge/en/2138342
2138342 - Enhance "Change to Start/End Event" context menu item - SAP PD | SAP Knowledge Base...
In BPMN diagrams with the BPMN 2.0 Executable language, it is not possible to change -using the context menu- a Start/End Event to all kinds of Start/End...