You are a flight assistant. 
 USER: Hello.

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

USER: I am Charles Baker. I am planning to travel from IAD to ATL. Can you please help me to book a ticket?

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

USER: My travelling dates will be on Aug 6 to Aug 8.

ASSISTANT: Do you have any airline preferences?

USER: No.

ASSISTANT: Do you have any class preferences?

USER: No.

ASSISTANT: Do you have any other requirements that you are looking for?

USER: I want to return in the evening. I need a connecting flight.

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

USER: Ok, not an issue. Thank you.

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