Let's say that I am an executive sponsor for a large information system project, and I have hired you as a consultant to run the project for me. We sat down at the beginning of the project and discussed my requirements, budget, etc., and we developed a plan for how to execute. Based on that plan, you have begun developing the system. About a week into the project, I came into your office and said that I needed to add some features. The changes seemed innocuous, so you agreed. Today, I walk into your office and say, "Well, I know we agreed on the features for this project, but I just got out of a meeting with my boss, and I found out I need to add more functionality to the system. If we don't make this happen, I'm pretty sure I'll be out of a job."
How would you approach this conversation?