Or: how to silence a persistent interjector, yet maintain your dignity and hers.
Here's how - check with the audience. It's so simple and easy it's almost funny. Let's take a specific example.
Amy is a thorn in your side. She's worked up about proposed changes in reception, when you're trying to tell the meeting about changes to the entire floor. On her last interruption she didn't take your hint that it's time to move on. And here she is again!
Amy: "Listen. I'm still not happy about the reception furniture. I think it's important to-"
You (Warm-eyed, putting your hand up in the stop position): "Just a moment, I need to check this..." (Look around questioningly.) "Is it useful to everyone if we stay with the reception furniture a bit longer?"
Now, whatever happens, you'll come out looking good.
If the audience is bored with Amy's interruptions, they'll shake their heads. In which case you won't hear from her again because it's very difficult to defy the weight of the audience wishes. Now, to preserve her dignity all you need to say to her (raised eyebrows) is, "Maybe we could have a word about it afterwards?"
But if the audience is interested in Amy's point, they'll nod their heads. In which case you return to Amy and invite her to expand on her point. You still look good because you're obviously willing to have open discussion about an audience concern. Of course you can't let it hijack your entire presentation - when you think the audience has had enough, look around questioningly and say, "Move on?" The audience answers, not Amy.
Neat, isn't it? The audience controls Amy, you and Amy maintain your dignity.