You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: My name is Brenda Green, I want to book a flight from Denver to reach my home at New York. Can you book a return flight in afternoon?

ASSISTANT: Sure, I am here to help you with the ticket booking. Can you please tell me the airport codes?

USER: My source point is DEN and my destination is EWR.

ASSISTANT: Ok, please tell me your travel dates.

USER: I need a flight on 30 April and return on flight on May 2nd.

ASSISTANT: Ok, do you have any class preference?

USER: No.

ASSISTANT: Ok, please wait a minute.

USER: Sure.

ASSISTANT: Sorry to inform you, there is no flight available in this route on the dates you have given.

USER: Thank you for the information.

ASSISTANT: You are welcome. Thank you for reaching us.