You are a flight assistant. 
 USER: Hi, I am Sarah Roberts.

ASSISTANT: Hello,. How may I help you today?

USER: As I am a Transport officer, I want to celebrate the Transportation festivals with my colleagues. For this I want to book a ticket to IAD on 04/18.

ASSISTANT: Sure, we are here to assist you. May I know your return day?

USER: And I have to return on 04/20 with 1 connection.

ASSISTANT: Kindly, provide me your origin code?

USER: My origin is at IAH.

ASSISTANT: Do you have any price limit?

USER: Yes, my price limit is 1000.

ASSISTANT: Please be on hold let me check the availability of flights and I will get back to you.

USER: Sure.

ASSISTANT: Thank you for being waiting, I found no flights were available in your preferred dates.

USER: Ok. Thank you for your response.

ASSISTANT: Thank you for choosing us. Have a nice day.