Strangers and older persons as well as people in official positions (e.g. in administrative offices, surgeries, clinics and shops) are addressed in Germany using the polite form of "Sie" and their surname. The offer to change the form of address from "Sie" to "Du" must come from the older person or the person "of higher rank" in the given situation. The "Du" form is used in the case of children and young people. Younger people and students generally always use the informal "Du" from the first meeting onwards.