Just ask Tori Pinellas. She and a colleague had forged an us-against-them bond while working at a local television station. “It was nice until our boss got promoted and they moved her into his position, making her my supervisor,” Pinellas recalls. “Let me tell you: She became a power-hungry monster.”

The change in their relationship hurt. “I cut her some slack at first, realising it must be awkward to all of a sudden be managing those you were working alongside the day before, but it became clear that she was not bothered by that awkwardness,” Pinellas says. “Needless to say, I became spiteful and started not to care, listen, respect and ultimately not to implement her decisions.”

Fighting your feelings

Bob Gunn says those feelings are normal. “Don’t feel guilty if, along with your good feelings for your friend, you also feel a tangle of negative emotion: jealousy, ‘why him or her and not me,’ sad or sorry for yourself, ‘now who can I share my frustrations with,’ anxiety, ‘oops, wish I hadn’t said those terrible things about the company or the boss’s boss.’”

But resist the temptation to wallow in your feelings. Focus instead on getting over them and getting back to work.

“Reflect on what you’re thinking. Sort out your emotions,” Gunn advises. Then try to see the new office landscape from the perspective of your old friend — and new boss.

Attention to attitude

“No matter how hard your friend (or you) are prepared for the new role, promotion brings a host of surprises,” he says. “There’s a chasm between watching or critiquing the boss and being the one responsible for sustaining an environment in which everyone can do good work. Your old friend or new boss has stepped out on a high wire, alone, juggling new pressures and decisions. From that perspective, turn your attention from what your new boss could or should do for you to how you can help him or her succeed — benefiting you and the company, as well as your friend.”

Doing so will not only help you deal more constructively with your feelings, but might just help you advance when the next opportunity rolls around.

To get yourself in position, Betsy Gullickson, Gunn’s co-author, suggests you:

Get very clear about roles. Remember the person, but show respect for his new position.

Be a good “wing man”. For instance, ask questions and insert comments that help sustain a positive tone and move discussion towards the goal.

Step up yourself. Now’s your chance to show that you can handle a greater share of responsibility and leadership.

Be proactive, and take the initiative. After all, you now have a boss who believes in you.

Friends in high places

When Scott Testa saw his office buddy get promoted for a job they both wanted, he tried to see the big picture: “It’s better to know who your superior is than if they hired someone from outside the company or department,” he says. “I was disappointed, but he was my friend, and friends don’t let friends down.”

So rather than turning your back on your old pal, get closer, Gullickson says:

Use your special history and shared knowledge of insecurities to help your new boss keep his bearings.

Haul him out from under the mound of work on his desk and talk about the non-work things you’ve always shared; you’d be surprised how rarely anyone asks the boss to lunch without some kind of agenda.

Help him laugh; lightening up is essential to keep one’s thinking clear.

“In short, now is the time to be a better friend than ever,” she says.