According to the PMBOK^® Guide, Change Control is the process of identifying, documenting, analyzing, approving or rejecting, and implementing changes to the project baselines.

Changes will happen, or at least be proposed, on your project. The purpose of implementing an effective change control system is to eliminate or at least significantly minimize scope creep from occurring. Scope creep is defined as the uncontrolled expansion to product or project scope without adjustments to time, cost, and resources. Scope creep is one of the most common causes for a project to miss its schedule and cost targets.

The specific change control approach for your project will depend upon your organizational change control process requirements. It will also depend on the size and complexity of your project. In some organizations, project managers have the authority to approve changes up to a specific cost threshold. Some organizations have a formal Change Control Board that reviews proposed project changes.

What is most critical is that a change control process EXISTS, and that proposed changes are identified as such, and not automatically incorporated into the project. The change control process should be documented in the Project Management Plan. 

Proposed changes go through the change control process, and are analyzed for impacts to schedule, cost, scope, and risk. Proposed changes should be communicated to key stakeholders, for any input or concerns they may have.

If a change is approved, it is incorporated into the baselines. In addition to performing schedule impact analysis and implementing proposed changes into the schedule baseline, you should document the reasons for the change, and any assumptions made or schedule risks that result. If there are new schedule risks, they must go through the risk management process.

You may need to update the resource availabilities to reflect any changes that occur, and also update the schedule based on resource changes and any cost information.

Detailing out existing requirements is not a change to the project. This is where things can sometimes become problematic – is this a new request, or just more detail about an existing deliverable? A thorough and detailed WBS can help minimize this challenge.

If a change is approved for your project, new tasks and links will need to be added to the schedule. The new tasks should be baselined, and any affected tasks should be rebaselined to incorporate impacts caused by the new tasks.

Note: If the current Baseline is not the original baseline that was set into Baseline10, you may copy the current baseline into one of the other available baselines, Baseline1 – Baseline9, before making changes, to save it for future analysis and comparison.