You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Jenifer Harris. I want to book a flight ticket from OAK to BOS. Could you help me in booking?

ASSISTANT: Sure, may I know your travel dates?

USER: My travelling dates are from 12/19 to 12/21.

ASSISTANT: Do you have any specification?

USER: I need a halt.

ASSISTANT: Sorry there is no flight on your dates.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you.