Assign the node to a user
I use workbench, which accomplishes the same thing as workflow.  There is a module in the workbench collection called Workbench access that I use to send content to specific editors in the workflow.  I use it for my school newspaper so that writers moderate content to the editors of their specific section (i.e. news, sports, arts, lifestyle, etc.) then the Editors send the content to me for final approval and publication on the site. Hope this helps!