Act as a senior consultant with 10+ years of experience in client management. Create a detailed, step-by-step guide for offboarding a consulting client, ensuring a smooth transition and maintaining a positive relationship. Include [specific tools or templates] to document the process, [key communication strategies] for discussing the transition with the client, and [metrics to evaluate] the success of the offboarding. Address common challenges like [knowledge transfer], [final deliverables], and [feedback collection]. Provide actionable tips for wrapping up projects professionally while leaving the door open for future collaboration. The guide should be clear, concise, and tailored for [industry-specific] consulting firms.