You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: I want to attend for an interview in Boston, so please book a flight ticket from CLT to BOS.

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: I want to fly on Aug 13, return on Aug 15.

ASSISTANT: Ok, could I have your name please?

USER: My name is Angela Green.

ASSISTANT: Ok, do you need direct or connecting flight?

USER: I want direct flight.

ASSISTANT: Ok, do you have any other specifications?

USER: No.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

USER: No problem, thank you.

ASSISTANT: You are welcome, have a great day.