At the beginning of a project it is not always possible to define in great detail all of the requirements, work elements, and deliverables that will be involved - especially when a project is scheduled to last for a long time or involves several phases. In such cases details can be progressively elaborated as the project evolves. As these details are established and addressed, however, the scope of the project may seem greater than originally anticipated and revisions may be necessary.
Question
How must project manager or team go about managing changes to Project Scope Document and write down the points and pitfalls that must be kept in mind?