Here is an excerpt from an article written by Wanda T. Wallace and David Creelman for Harvard Business Review and the HBR Blog Network. To read the complete article, check out the wealth of free resources, obtain subscription information, and receive HBR email alerts, please click here.

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If you’re a manager in a knowledge-driven industry, chances are you’re an expert in the area you manage. Try to imagine a leader without this expertise doing your job. You’ll probably conclude it couldn’t be done. But as your career advances, at some point you will be promoted into a job which includes responsibility for areas outside your specialty. Your subordinates will ask questions that you cannot answer and may not even understand. How can you lead them when they know a lot more about their work than you do? Welcome to reality: You are now the leader without expertise—and this is where you, possibly for the first time in your career, find yourself failing. You feel frustrated, tired and disoriented, even angry. This is the point where careers can derail. If you get to this point, or see yourself headed in this direction, what can you do?

First, you need to resist your natural inclination, which is to put your head down and work harder to master the situation. Leaders who come up an expertise track almost always derail here because they react to the challenge by relying on their core strengths: high intelligence and the capacity for hard work. They frame the challenge this way: “I need to master this subject. Okay, no problem, I’m smart. I can learn.” And so they buckle down, and dive into the mastering the details so they can be an expert again. This is the road to disaster.

It is a disaster because if it took ten or twenty years to master your specialty you are not going to achieve a similar mastery in a new domain in the first 90 days—and 90 days may be all you have before you have to show results. Your staff, who know a lot more about their domain than you do, won’t respect you, your lack of confidence in the details will show when you talk to top management, and your attempt to work twice as hard as you already are will wear you down.

So what should you do instead? To succeed in this situation, you must learn and practice a new leadership style. Your old style of management, which I call “specialist management”, depended on expertise. You need to put that behind you and adopt a new style of management: the generalist style. Based on my work with leaders who have successfully made the transition, here [is the first of] the four key skills to develop and practice:

1. Focus on relationships, not facts: One of the profound differences between the two managerial styles is that the specialist leader focuses on facts, whereas the generalist leader focuses on relationships. A specialist manager knows what to do; the generalist manager knows who to call. The specialist leader tells her staff the answer, the generalist brings them together to collectively find the answer.

How to focus on relationships: The single best tip for building relationships is to think about how you build relationships with clients and apply those same skills to colleagues. Spend a lot of time, face to face, getting to know people as individuals. In the generalist style you are constantly adapting your approach to the individual and the situation and that means knowing people very, very well. Flying overseas just to have dinner with an important colleague is not a waste of time—any more than it would be a waste of time to do so for a key client.

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Here is a direct link to the complete article.

Dr. Wanda Wallace is President and CEO of Leadership Forum, Inc., and author of Reaching the Top: Factors that Impact the Careers and Retention of Senior Women Leaders. Follow her on Twitter @AskWanda. David Creelman is CEO of Creelman Research. He researches and writes about human capital management.