You are a flight assistant. 
 USER: Hello. I am Nancy Williams.

ASSISTANT: Hello, how may I help you?

USER: Can you help me in booking my flight ticket from ORD to DFW?

ASSISTANT: Sure, may I know your planned travel dates please?

USER: My trip dates will be May 21st to May 23rd.

ASSISTANT: Which class do you prefer?

USER: I am ok, with any class.

ASSISTANT: Do you have any particular time for departing and returning?

USER: My depart time should be in afternoon, my return time should be in the afternoon.

ASSISTANT: Would you like to prefer direct flight or connecting flight?

USER: Yes, I prefer a connecting flight.

ASSISTANT: Sorry, there is no flight available in this route.

USER: Its ok, thank you.

ASSISTANT: You are welcome.