@Jim Tandy 

Typically you handle this in Flow Designer Actions as part of your main flow and can use the record reference to be made available in Action to manipulate input variables and process the data before making it available in subsequent sub flows and actions.

https://www.servicenow.com/docs/bundle/zurich-build-workflows/page/administer/flow-designer/referenc...

If you are referring to different functionality, please share screenshots of your configuration and functionality you are trying to achieve so as to provide more information.

If this helped to answer your query, please mark it helpful & accept the solution.

Thanks,

Bhuvan