I am Mary Brown, a sales representative who has been working in your company for ten years now. It has been a fruitful ten years for me and I have been working well under your supervision. I have gained a lot of valuable experiences and I have also learned numerous practical lessons about the sales industry.
I would like to express my humble request for a promotion. I believe that I can contribute more to the company if I be given a higher position and responsibility. Working under your supervision has trained me well and has given me much insight into the job of a sales supervisor. I know that I am ready to handle a higher position which you may see fit for me.
I hope to be able to meet you at your convenient time to discuss further my request.