This is the second assignment of level 3 advanced training in which we have to automate ACME site. first step was to changed the type of transaction item from queue item to data row I did that but at some places like this I am still getting the error.
first save the workflow, then just remove the assign activity and reflect the same assign activity manually.
or you can do cut assign activity once and paste it in the same place(original position )
In process >> in Finally>> change data type of transaction item
then delete transaction Item and Nothing and type it again
the error will be disappeared.