In Actionstep each matter has a primary contact you have to select for a matter. This article will show you how to add/change one.
First we need to go to Admin > Matter Types > Matter Type > Matter Type Settings > Parties Section
Once at the parties section in the matter type you will see all your participant types, as well as a few checkboxes, and one of them, is titled "Primary". Check the participant type you want to be primary then select save on the bottom left-hand side of the page.
Once the primary is set, at the top of a matter whoever is selected in that primary contact will appear.
This can be changed to any primary participant type you want.