Help with Workflow Builder

Looking for some help again. I'm setting up Manager Self Service and need some help with workflow functions. I have a procedure written that will update an employee's supervisor if their existing supervisor get terminated. I'd like to insert a function into the workflow process so that this will happen as part of the termination workflow. I need to pass the person_id for the terminated person, but I can't find examples of how to get that from one process/function to another or how to then pass it into my procedure. I realize this may be a simple question, but I'm