I agree with the previous responses, but I would add, not only put it down in writing but save it is a "draft" and give it a day or two or three, then re-read it and see if what you want to say to Corporate is really what you said in the draft. You want to be objective, not emotional, and sometimes, especially on what we say/type first off venting and not really objective. So in writing a letter to Corporate you don't want to come off as whinney. Just because your GM is a jerk, They already may know that, but be non-prejedicual ... What has he/she done to you and be professional, outling how there were threat, intimidation and bullying, that undermines productivity and what the the company stands for.
I need to write a letter to my company's corporate office in complaint of my general manager. There is a serious lack of professionalism from him/her. Threats, intimidation and bullying is not an effective way of managing employees. Please help?
Be blunt and to the point, confident yet modest and make it VERY clear that this other person is WRONG.
Maybe you can also get others opinons of how that boss treats them that would also help to get your boss reprimanded.