The only thing that's certain in today's business environment is that nothing is certain. Although change has always been inevitable, it hasn't always happened at the speed of light as it seems to now. The days of migrating upward into a cushy middle management job in a “safe” industry are gone.

Even monolithic companies are vulnerable to sudden change. Tides rise and fall — within industries, companies, and professions. Being in management doesn't protect you from those rises and falls. Rather, it offers opportunity and vulnerability in equal doses. You can't have one without the other.

Two examples of abrupt change in the business world are mergers and acquisitions. A company doing well buys out a competitor that is not doing so well. Sometimes the buyer is bigger than the company it acquires; sometimes it's a small company that has a big appetite. Companies often do very little to get their employees ready for these mergers and acquisitions. Beyond rumors, employees hear little and know even less.

A company's stock price is vulnerable to rumors, and quite frankly that becomes more important than the feelings and concerns of employees. Managers do sometimes get advance warning that a merger or acquisition is pending. They might even have a voice in determining who will stay and who will be let go in their departments.

If you find yourself in this situation, you'll quickly discover that it's a mixed blessing. On the one hand, the manager can help ensure that decisions are based more on merit rather than being utterly random. On the other, you must be fair and objective. You must also recognize and accept that you truly are in the middle. It is your role to carry out upper management's intentions and plans, even though you might feel your first loyalty is to the employees who report to you. As much as you would like to sneak in a few hints or even make a few midnight phone calls to certain employees to give them a heads-up, you can't.

No, it's not fair. But it is the only way to be equitable. No one enters into a job with the promise of perpetual employment (and few people really expect this to be the case). Companies exist for purposes beyond providing paychecks and benefits to employees, and in the end their objectives win out. Employees with the right skills and experience will stay; others will go. This is one of those times when it's nice to have performance evaluations and job descriptions handy. These bureaucratic annoyances become quite useful when it comes time to make objective decisions.

Mergers and acquisitions can be as difficult for the employees who stay as it is for those who are let go — managers as well as employees. If you are a manager who stays to become part of the new structure, you have your work cut out for you. Your cheerleader hat is going to get a lot of wear. Here are a few important tips:

• Always break the news to each employee individually, whether the person is staying or leaving. Although a group meeting might be easier for you, it could be very difficult for people who react emotionally to the news. There's nothing easy about hearing that the world you've become accustomed to has suddenly changed through no fault of yours — and that there's nothing you can do to change things now.

• Allow people who are losing their jobs to gather their belongings and leave with dignity. Some employees might want to say good-bye to their coworkers, but most people aren't very good with good-byes and prefer to leave without a lot of attention. People who are friends will arrange to meet if that's what they want to do.

• Meet with the surviving employees as soon as possible to explain what has happened and why. Hold this meeting in a location where it is safe for people to express their true feelings. They might feel angry that friends are now out of jobs and guilty that they still have regular paychecks.

• If your department is gaining new employees as a result of a merger, before they arrive, explain to the other employees why they are getting jobs when other people were let go. Sometimes all you can say is “That's just the way it is,” but it's important for you to say even this to acknowledge that employees need to hear a reason.

• When new employees arrive, welcome them and do your best to make them feel comfortable, even if you must set aside personal feelings to do so. It's not their fault that they're in this situation, any more than it's your fault.

Mergers and acquisitions often mean that new people and potentially a new corporate culture have to be integrated.

When Grapevine Applications and SophistiWare merged, it was a match made in heaven for stockholders but a clash of cultures for employees. Grapevine was a small company located just outside San Francisco. Its hundred or so employees were California-casual, wearing cutoffs and sandals to work. SophistiWare was a larger company based in Chicago. Its several hundred employees dressed to the nines — men and women alike wore trendy suits to work every day. Though Grapevine purchased SophistiWare, SophistiWare's president was tapped to run the new company.

Grapevine's employees were unhappy about this. Grapevine's president was a hands-on leader who knew each employee by name. SophistiWare's president, by contrast, was as formal as his attire. He didn't want to know names; he only wanted to see results. Doug, the Grapevine HR manager, tried to ease the transition for his employees. He met with them as a group to point out some of the strengths of the merger. “We're in a very competitive environment, and quite frankly our opportunities are shrinking,” he told them. “We need them, and they need us. It's about the bottom line and about survival, pure and simple.”

Doug let his employees express their concerns, but he held a firm line. People had no choice but to conform if they wanted to keep working at the company, and that was just the way things were. They needed to work together to make the adjustment to the new company's structure, procedures, and place in the market. Doug made sure everyone always knew what was happening and why, and how the changes affected jobs and responsibilities. To let people know he understood their concerns, he made jokes about finding a shirt and tie to match his cutoffs. This helped everyone to maintain some sense of commitment to a company that all knew would never be the same again.

Doug sent California employees to Chicago in small teams, to get to know their counterparts and better understand SophistiWare's processes. He also had small teams of Chicago employees come to the San Francisco office for the same reasons. When Chicago employees were visiting, Doug tapped into the department's petty cash fund to pay for a barbecue to let people socialize and get to know each other.

Although Grapevine's employees weren't happy about all the changes, they felt loyal to Doug and even to the new company because Doug rallied them into a support group for each other. They still had some bad feelings about the merger and the new company as a whole, but they formed positive feelings about the individuals they met. Although the road was sometimes bumpy, they continued to function as a very productive department.

You might feel fairly insignificant when others come in to restructure your department and the ways your employees work. But you're the only one, really, who can make it all work. Even if you feel you won't want to remain with the new company that results from an acquisition or a merger, it's in your best interests to do all you can to make the transition a success.

It's always better to leave on a high note, with people at various levels of the organization singing your praises. You'll feel better about yourself, and you might open doors you didn't know existed. People notice your actions and their consequences; it's up to you to shape them to present the perspective you want others to see and remember.