I assume you're needing to remove the background conversation?
That's the case you can try to remove it using the Cleanup tool. Highlight a 2 or 3 second section of background noise and then go to Cleanup... I don't remember the exact wording, but if you go right to the side menu it's at the bottom. The next to last will designate your selection as what you want to remove. The bottom choice will be grayed out until you do that, but then will be usable. You can either make another selection if you only want to process a certain portion, or you can just clear the selection and it will process the whole clip. How successful this will be varies from clip to clip and the quality / amount of the background noise you're removing.
Alternately, there's a Cleanup wizard, and one of the options is to remove background noise. So try both options and see how they work.
ETA, I'm sorry if the first paragraph's not clear, but I'm not at home to check the wording on the Cleanup options you need. I'll add that when I get home if needed.