What is not a reason for companies to organize Lessons learned?

A team member realizes that a technical update will improve a product's performance. What should the team member do before implementing the update?

You are the project manager for an information technology division of a large financial services firm in the United States. Your company offers a web based trading platform that provides options and futures trading for U.S commodities markets. Due to the rise in popularity of futures and options trading, your company has grown rapidly. To keep up with the demands you have been assigned with the responsibility of upgrading company's network and computing infrastructure. You have given the project charter progressively elaborated the requirements, and have just completed the Scope Definition and Create WBS processes. However while you are in the activity duration process you realized that certain deliverables are missing from the scope definition and create WBS processes. What is your next plan of action?

Risk mitigation involves______________

The project management office (PMO) assigns a project manager who specializes in hybrid approaches to a predictive project that is off track from both the cost and schedule perspectives. The project runs into further delays as the project manager is ramping up on the project. The stakeholders and ask senior management to replace the project manager.
How should the project manager approach this situation?