After years of climbing the corporate ladder, developing a person's skillsets, and mentoring them for the next chapter, you've decided it's time to finally grant that promotion. The employee has undoubtedly deserved to take that next step, complete with a title change, salary increase, profit-sharing perks, and maybe even that coveted corner office.

And then, things take a turn for the worse. Complaints from their colleagues, slipping numbers, and an overall drop in performance have now come to your attention. Now you can't help but feel one a deep sense of regret. Were you wrong about this person, after all? 

It can feel like a blow to have someone you've groomed to take over become a huge disappointment. It feels like a personal reflection of your leadership. Where did you go wrong?

But not all is lost quite yet. Here are three things to do to try and turn things around. 

1. Act fast.  

If there's one piece of advice you take away from this article, let it be this: don't wait. The longer you let things slide, the more it havoc it can cause. The first sign of performance falling or an ego rising needs to be addressed immediately. Otherwise, relationships will become strained, the company suffers, and morale goes out the window. And then there are your own stress levels to consider. 

There's no time like the present. Act fast and swiftly. Is the team they're managing complaining about their leadership style? Address it in 24 hours of the complaint. If you see that the person is struggling in the new role, don't throw him in the deep end and hope he learns to swim. Be the liferaft that can bring him back on course. 

2. Have you set expectations?

Just because you're clear on what's expected of them, doesn't mean they are. Unfortunately, not everyone "gets it". People need clear goals and guidelines on how they should perform in their new role. What may seem obvious to you isn't to others, especially if this is their first time in a management position. 

It's time to get real specific. From sales goals to leadership techniques to office conduct, don't leave any areas grey. Make things black and white. In other words, no you can't spend $1,000 on a new television screen for your office, or ask your executive assistant to wash your car. Yes, you are expected to do quarterly one-on-ones with each staff member and report their feedback, good and bad, to your superiors.  

3. Set a deadline.

Now that you've addressed the issue and set expectations, it's time to keep the person accountable. Give them three months to start turning things around. Whether that's improving their management skills, hitting their sales numbers, toning down their entitlement, or a combination of all three, let them know that you need to see a drastic improvement by a certain date.

Then, follow-up on that. Talk to the people on their team and the clients they deal with to see if things have improved. Ask for a full sales report, as well as a strategy to continue upward trajectories. While no one likes to babysit, if you saw enough potential in the person to give them the promotion in the first place, give them a chance to prove themselves in the position. 

And what happens if things don't get better? Well, you know what to do. If it turns out they're not cut out for the role like you'd hoped, there's only one place for them to go, and that's out the door.

Demotions or "re-training" is not going to be good for you or them. They've had their chance to prove their title, and unfortunately, they've lost it. Now you've got to do what's right for your business, and reassess the next time you offer the next title bump.