If you are a presenter that tends to roam around the audience, you can walk over and stand by the negative person. This often gets them to change their behavior because they become uncomfortable having everyone's eyes on them.
In worst case scenarios, you may have to ask the negative person to leave. In my fifteen years of speaking, I have only had to do this once, with two individuals from one company. Ironically, the company had hired me to help them improve the morale of workers and their interaction with leaders. Two of the individuals did not want to be there. One sat slumped in his seat while the other one sat with his back to the room and stared out the window. At one point, the question was asked, "How should I handle it when a customer asks me to work on a project but they haven't gone through the proper channels to get a number assigned to the project? And a number needs to be assigned to the project in order for us to properly track time and pay." Mr. Negative turned around from staring out the window and said, "This is just a bunch of bull____. I just tell the customer we can't do that and I hang up on them."
At this point, you could have heard a pin drop in the room. And all eyes moved to me to see how I would respond to the situation. I knew, because of the topic we were covering, that my primary goal as presenter was to make the room safe for people to ask difficult questions. And Mr. Negative had just killed that safe environment.
So, I used Outcome Thinking® to address with the group what we were trying to accomplish and how they needed to act in order for us to achieve that. I then gave them the option to stay or leave, but if they stayed they were agreeing to participate positively.
Then I gave the group a 15-minute break so they could choose whether they wanted to stay or leave. At this point I had only been speaking for about forty minutes, so we were not really at a point in a full-day session where you would normally take a break.
Ironically though, every single person came back, and the two negative people sat up front and participated. The feedback forms that came back to me repeatedly said, "Thanks for making it a safe environment to talk."
Want more examples on how to handle a negative person? Take a look at Anne’s book, Outcome Focus® Approach: How to be Become One with Your Audience. Go to the Product tab and click on Books.