When working on a project (both professional and personal), change can cause problems. Particularly in our modern age of quick and simple electronic edits, it can seem that a minor change is as simple as just making the change. Understanding the full ramifications of the change is critical to a smooth project.
Consider changes even to team meetings. I wasn't included in an original meeting request because I was on vacation at the time. But when the meeting was re-scheduled when I was back in the office, I wasn't included on the updated meeting notification. I was surprised to be called in to a meeting that I was unaware of and unprepared for.
Consider a kitchen remodel project, with a change to the configuration of the cabintry. If the entire planned cabinet plan isn't checked against the new change, there could be a big giant void in the finished kitchen. This story has often been told on HGTV and also happened to one of my co-workers.
A well planned project will have written change orders, which are signed off on by project stakeholders. These change orders will carefully and deliberately reconsider all aspects of the project in light of the change.