Budget consists of the total estimation effort (or quantities) necessary, and the cash flow required, to complete a project. Before a project start, the resource/cost manager, along with the operations executive, program manager, and project manager determine scope and budget requirements, and set these estimates. As requirements change, resource and financial support are adjusted to compensate for these changes. The individuals involved in project funding and financial support can log changes to the budget in the project planning stage, or after the project is underway. P6 Professional tracks these changes, while retaining the original amounts.