A risk actionee in PRINCE2 is responsible for managing, monitoring, and controlling all aspects of a specifically assigned risk. This role includes planning and implementing appropriate risk responses and ensuring that the risk is handled effectively throughout its lifecycle in the project.References: PRINCE2 Foundation Manual

Maintaining the business case during the project lifecycle involves regularly updating it to reflect changes and actual experiences such as incurred costs. This ensures that the project remains viable and aligned with business objectives, as part of the continual justification process. The business case is dynamically managed to reflect any changes in the project's environment and is a fundamental part of the 'business case theme' in PRINCE2.References: PRINCE2 7 Foundation source documents on business case management.

Effective communication within a project in PRINCE2 focuses on ensuring that messages are clear, consistent, and reach the right stakeholders at the right time. This involves targeting key influencers who can aid in further disseminating information throughout the project, thereby enhancing communication efficiency and effectiveness.References: = PRINCE2 7 Foundation Training Manual and official PRINCE2 website documentation

The Benefits Management Approach in PRINCE2 is a document that describes how and when a measurement of the achievement of the project's benefits, both during and after the project, can be made. It is used to assess the performance of the project's products once they are in operational use, ensuring that the project delivers the intended benefits as outlined in the Business Case. References: PRINCE2 7 Foundation Handbook and official training materials.

According to PRINCE2principles, the business case theme requires documenting the management actions necessary to ensure benefits are realized. This involves planning, measuring, and managing the realization of benefits, and it's critical for maintaining the relevance and justification of the project. References: PRINCE2 Foundation Handbook, Business Case Theme section.