A person is very bulky with muscle, but he needs to lose some muscle. How can he get rid of excess muscle????

Answer 1

Stop training. Get him to eat just twice a day instead of 5 to 7 meals a day. The reason is when he stops training, the muscles will stop shrinking. When he starts to eat less, his body will start to feed on his muscles for nutrition.
One of my friend did the same thing when his Girl friend started complaining about how big and muscular he looked when he is standing next to her.
Last but not the least.... get him to start training with less intensity ( not his usual training routine) and normal eating habits when he has reached the desired muscle mass. This it to maintain or else he is going to put on weight. Hope i have answered your question.

Personally, why would you want him to loose all those muscles that some guys would kill to have.

Answer 2

Muscle mass is only maintained by consistent effort, so if you stop training you will lose muscle definition. It won't take long either.