Send to Design
A compatible unit (CU) can be sent to the Design tab on the Attribute Editor from a few different places. How Designer assigns the work function depends on how the CU is sent to the Design.
Selection tab: Right-click and select Send to Design. You may use the Work Function Tool to modify the work function.
CUs tab: Select a work function in the Work Function field at the top of the tab, right-click the feature and select Send to Design.