How to determine valid parameter names when submitting HCM Extract flow via SOAP call

Hello,

Background: I am using Oracle's FlowActions Webservice and am specifically calling the 'submitflow' operation in OIC. When I call this service with one parameter (Effective Date), the flow is submitted, and the HCM Extract outputs data as expected to the UCM, which is the delivery method I've set up on my HCM Extract.

However, as soon as I add a second parameter (Changes Only) to my mapping, the extract only outputs my header row to the UCM. When I run the HCM Extract manually within the UI with the exact same parameters that I am using in my SOAP call, the HCM Extract outputs with header and data into the UCM as expected. This means that there is an issue with my SOAP call and not with the HCM Extract or the report it is connected to.