Being a place to learn leadership is one of the purposes of Toastmasters. If you are an Area Governor, President, Immediate Past-President or a long time Toastmaster, you should work with the under performing officer to improve. Talk to the officer after the meeting. Why do you feel that they are under performing? What suggestions do you have to help them improve? Is this sounding a lot like an evaluation? Another good source of ideas is the "Coaching" project in the advanced manual Interpersonal Relationships.