I do not understand what you mean with Route to a sub case. What you do here is Creating a subcase. The subcase itself will now follow it own life cycle and if there is an assignment in the "SWDeveloper Case" the subcase will be there to be worked on. The work items should be in the work list or work basket defined for that assignment. You might need to go to the Case Manager portal to open that work list or basket.
Thanks for your reply Bernving.To be more clear with my question,here is what i am trying to do.I want to route a candidate to another subcase on the basis of their designation whether they are a software developer or a software tester,according to which they will be routed to a separate sub case Sw developer or Sw Tester,on completion of which the control should come back to the original case.