This role usually is taken by the boss, authority, department manager, foreman, supervisor or something like that. The transition for this person won’t be difficult - the only change is the approach and method distribution of tasks to the team. For exchange the Project Owner gets very accurate information of the business value and especially of the required product development resources, and thus the Project Owner can calculate practice-oriented prices and present accurate deadlines for the customer. The person who is going to be the Project Owner is responsible for defining the tasks and prioritizing them - the Project Owner decides what work has to be done first and he is responsible for the Scrum Backlog.
The Project Owner will get constant feedback from the Scrum Board and every tow weeks he also gets a nice retroperspective from the Team. After each Sprint -the two weeks product shipping cycle- Scrum makes by design sure that there is at least one product ready to ship, done and tested.
A good Project Owner only cares for a testable end result of a product. A bad Project Owner tries to care about how stuff is actually build, because that’s the job of the Team.
It is important to understand that Project Owner doesn’t determines process of team work, he determines only what comes out of the process.
The Scrum Master is like a mediator between the Team and the Project Owner. Starting with agile development, the “Scrum Master” is a full time job. Working with high and hyper productivity teams it also is a must to have the Scrum Master around every workday. For normal agile teams, already knowing how to run Scrum, a good Scrum Master can manage another agile team, or he can become also part of the Team, to get more work done.
In an working agile Scrum Team, a traditional project manager is not needed, and might even do harm. The Scrum Master is someone who makes sure that the Scrum process runs smoothly, and he is in charge to protect the team from disturbance and to identify and to remove “impediments” (things that keep the team of work). This person needs to manage the process, keep it running well and make sure that rhythm is maintained.The Scrum Master is not the boss, His job is to take initiative and remove problems which slow down the productivity or give the team a hard time. The Scrum Master finds solutions to problems, no matter whether they are fundamental weaknesses of the company, obstacles in the work routine or interpersonal problems inside the team.