SAP Message V6810 - Combinations of actions (e.g. Create + Delete) are not allowed per HU

Diagnosis
You want to create and change a handling unit in one step.
This is not possible. The function module SD_SHIPMENT_PROCESS_HU canonly create a HU or change an existing HU, not both, during a run.

Procedure
Check the contents of the calling BAPI (BAPI_SHIPMENT_CREATE).