If you’re the type of person who cares about conversational etiquette, the idea of interrupting someone might make you cringe. But sometimes, cutting in is necessary.

However, you should only do it if your conversation partner is “saying something factually inaccurate,” says Jefferson Fisher, a Texas-based lawyer and author of The Next Conversation: Argue Less, Talk More. “It’s not that you’re arguing with their opinion; you’re arguing an actual issue of legitimate fact.” With the right words, you can do it in a way that (probably) won’t irritate whoever is on the receiving end.

Be upfront
The best way to interrupt someone is to acknowledge what you’re doing. Start with the words “I know I’m interrupting” or “I need to interrupt.” With this preamble, “people don't get defensive, because it’s you acknowledging what you’re doing,” Fisher says. “If you’re talking and you said something inaccurate, I would say, ‘Angela, I need to interrupt you,’ or ‘I know I'm interrupting you.’ You won't see it as an affront or as me just assuming that what I’m saying is more important than what you're saying.”

Read More: How to Say ‘I Told You So’ in a More Effective Way

The same philosophy applies to social gatherings. If you want to steal someone away who is already in conversation with another guest, announce what you're doing instead of grabbing the person’s arm and pulling them away. “If somebody comes up and says, ‘I need to take Angela for a minute,’ and then pulls you, now I understand the dynamic,” Fisher says. “It’s like giving a roadmap for what needs to happen.”

Voicing what you’re doing is almost always useful, he adds. If you're in an argument with someone and you suddenly slam the door shut and leave the room, for example, it probably won't go over well. If you explicitly state that you need to leave the room, however, you’re at least making your intentions clear and setting expectations. “When you claim it, you control it,” Fisher says. “When you say something out loud, it shows your confidence in what you’re doing, which is powerful in communication.”