A May 2013 press release by the University at Buffalo notes that approximately 35 percent of employees in the United States have reported being bullied at work. Workplace bullying occurs as overt or covert aggression. Overt tactics such as shouting and hitting are obvious, but covert schemes are hidden and often difficult to prove. Habitual manipulation is a powerful tactic that covert aggressive personalities use to achieve their goals. Underneath your manipulative colleague’s friendly and charming exterior is a highly destructive individual whose goals are power and control.

Dealing With Communication

Manipulators do not communicate openly about what they want. Instead, they resort to flattery or play the victim to gain your trust and sympathy. For example, whenever your co-worker praises you, she asks you to help her finish a task right after. So she knows you prefer honest communication, you might say "I notice every time you say something nice about me, you ask me for a favor. I would prefer you being more upfront with me about what you need." Manipulators tend to target people they view as weak. By openly confronting her behavior, you show that you're not easily manipulated.

Listening to Your Gut

Manipulation is normally felt, rather than heard or seen, so you must listen to your gut. An article by Dr. George Simon says if you’re dealing with a covert aggressive personality, he's probably aware of his actions. If you confront him about his behavior, he may pretend he doesn’t know what you’re talking about or act offended. This is why you must listen to your instincts. For instance, your co-worker says he's about to call in a lunch order. He asks all the members of your team if they would like anything on the menu, except you. This might be his way of humiliating you for a real or perceived slight. Acknowledge what your instincts are telling you, but do not react to his action. Instead, limit your dealings with him to work-related matters.

Trusting Your Co-workers

If you feel you can’t trust this person, then don’t reveal anything personal about yourself to her. Though she might look trustworthy, once the opportunity arises, she won’t hesitate to use what you told her against you. Find other employees who have earned your trust and share your experiences with them. They’ve probably gone through what you’re experiencing with that same person.

Counteracting Sabotage

Do not put it past your co-worker to sabotage you to advance her career. For instance, she always emails you about minute details concerning your work. She also copies your boss on these emails and offers to fix what she perceives as your errors. To counteract such behavior, always do your best work so her complaints remain unwarranted. She might also take credit for your accomplishments and ideas or insert errors into your work. Write down your ideas and share them with your boss before revealing them to your co-worker. Maintain a detailed account of joint projects, including the date and time of correspondences you have with her. Lock your computer when you're away from your desk and minimize the computer screen when you're not using it.

Addressing Behavioral Patterns

Manipulative colleagues adhere to a pattern, says Dr. Mildred L. Culp, an expert on workplace issues. Because manipulators follow a pattern, their negative behavior tends to catch up with them. If you’re patient and smart, you might last longer on the job than them. Meanwhile, pay attention to trends in your manipulative co-worker's behavior. Write down these patterns and any witnesses in case you need to report him to your human resources department or manager.