Each project in its life cycle goes through several stages. When one phase is over, next one begins. Certain project processes last throughout whole project life span and this thesis focuses on change management and risk management. Changes to the project happen constantly and are inevitable, so it is important to know what changes are needed to make the project more successful, and which changes are insignificant or have a negative impact on the project. Improper management of changes increases the risk of negative impact on the project outcome and can result in increased costs, prolonged project duration, or even unsuccessful project execution. The project manager must have experience, knowledge or skills to be able to judge what change the project needs. Sometimes, depending on the size of the project, project manager can also be assisted by a separate board that handles change and makes decisions about making changes. In this thesis, the project change management process will be presented on a real project of buying new buses that, through improper change management, had negative financial implications when the project outcome was put to use. In addition to this specific example, there will be projects that have been carried out in the previous period and it will be explained how they responded to changes over the life of the projects and how it affected the economic and social elements of the environment.