>>4230
I'll leave a couple of examples
계세요? (When asking if anyone is home, it is enough to say this)
선생님은 오늘 사무실에 계세요? - Is the teacher in the office today?
집에 부모님들이 계세요? - Are your parents at home?
versus 있으시다
혹시 빌려줄 수 있는 연필이 있으세요? - Do you happen to have a pencil you can lend me?
여자친구가 있으세요? - Do you have a girlfriend? (if you say "여자친구 계세요?" you are asking if she is there)
Saying something like "자동차 계세요?" doesn't work at all, as 계시다 is only used when talking about the existence of someone.