1. When you ask someone for something and he/she agreed to your demands, you can use ''麻烦您(了)'' to express your thanks. In this situation, "麻烦您" means "thanks".
EX: "May I have a cup of coffee?" "Of course." "麻烦您(了)"
2. When you ask someone for something and want to be polite, you can use "麻烦您" to begin. In this situation, "麻烦您" means "please".
EX: "麻烦你帮我倒杯咖啡好吗 = May I have a cup of coffee please?"