You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you?

USER: I want to fly from IAH to DCA to meet my parents, can you please book a flight ticket?

ASSISTANT: Sure, I can help you. Can I know your travelling dates?

USER: Sure, my journey dates are Aug 05 and Aug 07.

ASSISTANT: Do you require any break?

USER: Yes, I need a flight with single connection.

ASSISTANT: May I know your name?

USER: I am Helen Roberts.

ASSISTANT: Thank you for the information. May I know if you prefer to have any other comforts in your journey?

USER: I prefer a departure time at evening.

ASSISTANT: Ok. Give me a minute.

USER: Sure.

ASSISTANT:  We are unable to provide flight in between your journey routes due to some technical up-gradation at destination airport.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us.