Final answer:
The first action should be to streamline the documentation process by revising the existing form to make it more user-friendly and comprehensive, before considering further training or feedback systems.
Step-by-step explanation:
When a nurse manager discovers that the documentation of client discharge teaching is below the expected benchmark, the first action should be to identify the root cause of the issue. If the problem is with the documentation process itself, then Option 2: Revise the existing discharge teaching documentation form to make it more user-friendly and comprehensive, may be the most effective immediate step. This could involve simplifying the form, clarifying instructions, or integrating prompts that ensure all necessary information is recorded. After streamlining the documentation process, the manager could then consider additional training, individual meetings for personalized feedback, or a peer-review system to maintain and improve the standard of documentation.