According to the PMI Guide to Business Analysis, change control systems are tools that help to manage changes to requirements or other project deliverables throughout the project life cycle. Change control systems include provisions to implement changes without formal review in the event of an emergency, such as when there is an urgent need to fix a critical defect or issue that affects the project scope, schedule, cost, quality, or risk. However, when this provision is utilized, changes must still be documented and captured in order to maintain traceability and accountability of the changes, and to communicate them to all relevant stakeholders. Documenting and capturing changes also helps to avoid any confusion or inconsistency in the requirements or other project deliverables, and to evaluate their impact and outcome. The risk associated with the change is still evaluated before implementing it, even in an emergency situation. A change control board should already be established as part of the change control system. Changes may still require further managerial involvement after they are implemented in order to monitor and control their effects. References: PMI Guide to Business Analysis, page 288-289.