The RACI model can be used successfully in step 6. It is a straightforward model for identifying roles and responsibilities.
Responsible: The person who does the work to achieve the task, i.e. make getting the work done or making the decision. As a rule, this is one person only.
Accountable: The person who is accountable for the correct and thorough completion of the task. This is often the supervisor or manager who approves the work.
Consulted: The people who provide information to achieve the objective, and with whom there are two-way communication. This can include customers, suppliers, subject matter experts.
Informed: The people who should be kept informed of the progress, usually one-way communication. This could include higher level management, customers and suppliers.