Adapted from “Their Agent, Your Advantage,” by Guhan Subramanian, Professor, Harvard Business School and Harvard Law School.

The benefits of hiring an agent are well known. Yet negotiation experts often overlook the ways in which you can use the other side’s agent to your advantage.

Suppose you’re stuck in contentious negotiations with the other side’s agent. How can you break an impasse? Threaten to bring the agent’s principal—the person he represents—to the table.

Consider the real-world case of a record-company executive who was negotiating with an up-and-coming musician’s agent over a recording contract. At several points during the talks, the agent demanded perks that would benefit both the musician and the agent, such as first-class travel for both the musician and her staff. Brief encounters with the musician had led the record-company exec to believe that the musician cared less about these perks than the agent claimed.

After several frustrating negotiating sessions, the exec said to the agent: “I don’t think you’re adequately representing your client’s interests here. I’d like to take these issues straight to her.”

This is a high-risk tactic, as it threatens your relationship with the other side’s agent. Nevertheless, it can be an effective way of breaking impasse and even achieving concessions.

Consider the agent’s options when confronted with the threat. If the agent is knowingly misrepresenting his principal’s interests, he inevitably will cave to avoid having this misrepresentation revealed to his client. Even if the agent isn’t deliberately misrepresenting the musician’s interests, he may cave if there’s some chance the musician might repudiate his demands. In addition, to avoid the risk of losing the client’s trust, the agent may capitulate even if doing so is not in his principal’s best interest. The lesson: When a negotiation has stalled, threatening to “go upstairs” can put you back in control.