Mary was the office manager for a large construction company - and with her keen eye for detail, she ran a tight ship. She had the respect and loyalty of both her employer and her staff - but when her boss cajoled Mary into taking on his daughter Bianca for a university work placement, things rapidly began to slide downhill.

Bianca was an only child and the apple of her father's eye. Mary felt that her boss had a blinkered view of Bianca's abilities and privately, she felt that the young woman had a "Princess" attitude.

Fed up with having to remind Bianca to follow office procedure - and aware that the others in her team were being negatively affected by her airs and graces - Mary had turned to me for help.

Clearly Mary felt that she was in a no-win situation. Admitting that she'd never have recruited Bianca in the first place, she also knew that her boss wouldn't take kindly to her complaints about his daughter. But she could also see that she was rapidly beginning to lose credibility with the rest of the team, who expected Mary to sort things out.

I asked Mary what irritated her most about Bianca. "Well," she replied, "she's lazy, she won't do the mundane tasks that we all have to do and she seems to think that we're lucky to have her. But I'm sick and tired of having to nag her to do simple tasks."

It was an educated guess, but I suspected that it was the nagging that was making a bad situation worse. "I can so understand why you feel the need to remind her what needs to be done," I said, "but perhaps she can't understand why you want her to do these tasks. And maybe she's pretty thick skinned and has simply learned throughout her life that if she doesn't do something, in the end someone else will do it for her!"

Mary looked cross. "Well, I hope you're not going to start making excuses for her!"

"Certainly not," I replied. "But understanding what's going on is the first step. Now all we need do is find a way to motivate her. For example, many of us find it easier to get motivated to do something when we understand why it's important for us to do it. Helping her to see the bigger picture in this way will help a little.

"It would also be beneficial if you could organise a mini-appraisal with her. Ask her how she's enjoying the job and what would make it better from her perspective. You could also get her to think about how she's fitting in with the rest of the team. You could also take the opportunity to find out what her career aspirations are - and give her some guidance as to the kind of behaviours she'll need to exhibit if she's going to succeed."

Mary nodded slowly, seeing the sense in my suggestions. But I hadn't quite finished. I had an ace up my sleeve.

I continued, "The key to successful communication is to reinforce the behaviours you want! When Bianca does something right, praise her. When she gets it wrong, make as little fuss as possible. As humans, we like to fit in and be praised - so subconsciously, we choose to do more of what wins us praise and less of what doesn't. All the time that you're nagging at Bianca, she's ignoring what you're saying because it doesn't feel good! Reinforce her positive behaviours and without realising why she's doing it, you'll start to see her attitudes changing."

Mary promised to give it a go - recognising that perhaps she had little other choice. But when we caught up for a coffee and a chat a couple of months later, she was almost evangelical!

"I could never have believed that I could make so much difference in someone else," Mary had told me. "While it felt uncomfortable for me at first - especially as I didn't feel that Bianca actually deserved any praise - I did my best to focus on the behaviours I wanted from her, rather than on those that I didn't want. The results have been almost miraculous. And I knew I'd got it right when Bianca's father - my boss - took me out for lunch week to thank me for teaching his daughter how to be more professional at work."