You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Helen Smith here. Can you please help me in booking a flight ticket for round trip from IAD?

ASSISTANT: Sure, can you please share your travel dates?

USER: Yes, I would like to travel on July 31 and return on Aug 2.

ASSISTANT: Do you have any class preference?

USER: No, I am comfortable with any of the class.

ASSISTANT: Helen Smith, there is a flight available with price 200 and the connection is 1 with AA airline. Would you like me to proceed with the booking?

USER: Sorry, I need direct flight due to some urgency.

ASSISTANT: I am sorry to inform you that there is no flight available at your request.

USER: No problem, thank you for your kind service.

ASSISTANT: Thank you for contacting us.