You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you for today?

USER: Could you please help me in  booking a ticket from IAH to DCA where I have a meeting to attend.

ASSISTANT: Can you please share on what dates you are willing to travel?

USER: My itinerary travel dates are as follows Oct 14 and Oct 16.

ASSISTANT: Are you looking for a connecting flight or direct flight?

USER: I would like to board a single connecting flight where the depart should be in the evening.

ASSISTANT: Do you have any class preferences?

USER: I have no more preferences.

ASSISTANT: Can you please provide your name to proceed further?

USER: My name is Ryan Carter.

ASSISTANT: Sorry, there are no flights available at your request.

USER: No issue, thank you for the time.

ASSISTANT: Thank you for contacting us, have a nice day.