As the old saying goes, "Be careful what you wish for!"

Not every promotion or new job leads to happiness. In some cases a job seeker may discover that a seemingly promising promotion ends up being a huge headache, instead.

"It happens," says Pamela Slim, career coach and owner of Ganas Consulting, Mesa, Ariz. "You think accepting a promotion is the smart thing to do, then you realize that you don't like what you're doing anymore."

What to do? Ask for your old job back?

Not until you've given yourself a fair shot at getting accustomed to your new role and responsibilities, says Anita Bruzzese, a syndicated newspaper columnist and author of "45 Things You Do to Drive Your Boss Crazy... and How to Avoid Them," (Perigree, 2007).

"A lot of people have trouble with changes," Bruzzese says. "You have to give it time."

It may take up to one year to feel at ease in a new job, she adds. Discomfort may not mean a new position is a bad fit. Remember, a promotion should challenge your skills and knowledge.

Bruzzese suggests that if you're not satisfied with your new gig, you should discuss it with your boss. Start by asking for a more clear description of expectations. You may need a better plan, or road map, for acquiring the new skills.

Also consider seeking a mentor or coach who can help with the transition.

If you're still feeling uneasy, it may be time for a different sort of discussion with your boss.

Slim says the culture of an organization will help you determine whether it's wise to ask for your old job back. Ask yourself if the organization places a strong emphasis on developing individuals and learning. Is it safe to admit that you made a mistake?

But even if the culture is open to team members pursuing their individual strengths, Slim says you should still play out all scenarios in your mind to evaluate how taking a step back could affect your career goals.

"Ask yourself whether, if allowed back to your old role, you'd get a reputation as someone who is not a high performer," she says.

Difficult personal situations or family responsibilities might force you to reconsider a promising but challenging new position. It is important to understand that going back to an old job may have an impact on future promotions, career coach Pamela Slim says. You may need to look outside of the company for advancement in the future, she says.

Repercussions from a change of heart are all but inevitable, Bruzzese believes. First, your manager is likely to feel that he or she made a wrong decision in encouraging your promotion. Then, that individual will be forced to spend time searching for, hiring and training a replacement. The company will spend more money in headhunter fees, employment ads and lost time.

"It's tough because someone had to have had faith in you and believed that it would be a good fit," she says.

Slim says once you've taken all scenarios into consideration, be true to yourself and honor your needs.

Because of the number of hours we spend at work, job satisfaction is crucial to our overall sense of well-being. Additional financial compensation may not make up for a loss in job satisfaction. The key is to identify the skills, experience and abilities that energize you and make you happy while doing them, Slim adds.

Do you really want your old job back? Take the bull by the horns. Do what is best for you.

Depending on the situation you can either tell your boss that your life has changed since you received the promotion (perhaps you take care of an elderly parent or have a chronically ill child) and that you're no longer able to handle additional responsibilities.

If you're simply not happy with the new demands, Bruzzese suggests trying to save face by explaining that your new job does not play to your strengths. "Say, I want to use my skills to do the best for the company'" she suggests.

Regaining the trust and support of management may take time. But if you're back in a position in which you thrive and you feel energized, you'll work with passion, she says, and eventually shine again.

Once you're in a good spot again, chances are you won't regret having wished for it.