message cancelWorkItemRequest
parts 
cancelWorkItemDoc
element dto:cancelWorkItem
used by 
Operation cancelWorkItem in PortType WorkItemSchedulerService
source  
<wsdl:message name="cancelWorkItemRequest">
  <wsdl:part name="cancelWorkItemDoc" element="dto:cancelWorkItem"/>
</wsdl:message>

WSDL documentation generated by XMLSpy WSDL Editor http://www.altova.com/xmlspy