Email is a communication tool that allows the project manager to send information to one or more recipients without requiring immediate feedback or confirmation of receipt. Email can be used to broadcast information that is not urgent or critical, such as status updates, meeting minutes, or general announcements1, p. 75

Infrastructure as a service (IaaS) offers administrators more direct control over operating systems than other cloud service models. IaaS is a type of cloud computing service that provides virtualized computing resources such as servers, storage, network, and operating systems over the internet. IaaS allows users to rent or lease infrastructure resources on demand and pay only for what they use. IaaS gives users more flexibility and control over their infrastructure resources and enables them to configure, manage, and customize their operating systems according to their needs and preferences3

A ticketing system is a tool that allows the project manager to assign, track, and manage tasks for the testing phase. A ticketing system can help the resources to remain at their desks and only react when needed, because they can receive notifications, updates, and feedback on their tickets through email or other channels. A ticketing system can also help the project manager to monitor the progress, quality, and issues of the testing phase, and to generate reports and metrics. A ticketing system is different from a videoconference, which is a tool that allows the project team to communicate and collaborate in real time through audio and video. A videoconference is not suitable for allowing the resources to remain at their desks and only react when needed, because it requires their active participation and attention. A ticketing system is also different from a simple messaging system, which is a tool that allows the project team to exchange text messages and files. A simple messaging system is not effective for assigning, tracking, and managing tasks for the testing phase, because it lacks the features and functions of a ticketing system, such as prioritization, categorization, status, and history. A ticketing system is also different from a corporate social media, which is a tool that allows the project team to share information and ideas through online platforms. A corporate social media is not appropriate for allowing the resources to remain at their desks and only react when needed, because it may not be secure, reliable, or professional for the testing phase. References = CompTIA Project+ Study Guide: Exam PK0-005, 3rd Edition, Chapter 10: Project Execution1; CompTIA Project+ Certification Study Guide, 3rd Edition, Chapter 10: Project Execution2; The 15 best collaboration tools for productive teams3

The closing phase is when the project manager and the team finalize the project, deliver the outcomes to the customer, obtain formal acceptance, conduct lessons learned, and hand over the project to the operations team. Identifying the baseline go-live date, the operational training, and the handoff procedures are part of the closing activities that ensure a smooth transition and closure of the project. References = CompTIA Project+ Study Guide: Exam PK0-005, 3rd Edition, Chapter 14: Closing Projects, p. 333-334.

When implementing an IT infrastructure change that takes risks into consideration, the project manager should develop a rollback plan. A rollback plan is a contingency plan that outlines the steps that need to be taken in case the change does not work as expected. It includes a plan to roll back the changes and restore the system to its previous state. References: CompTIA Project+ Study Guide Section 3.3.
The project manager should develop a rollback plan when implementing an IT infrastructure change that takes risks into consideration. A rollback plan is a contingency plan that describes how to revert back to the previous state of the system in case of a failure or disruption during the change implementation. A rollback plan can help to minimize the impact of the change on the system performance and availability and ensure business continuity and data integrity.