What is the best way to handle an intoxicated guest and discontinue service?

The best way to handle an intoxicated guest is to approach them calmly and respectfully. Politely explain that you can no longer serve them alcohol due to their current state, emphasizing concern for their safety and well-being. Offer them non-alcoholic drinks and suggest alternative ways to enjoy their time, such as food or entertainment. If needed, involve a manager for support and to ensure a smooth resolution.