You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I am planning to book a flight ticket to LAS from DFW, can you please help me out?

ASSISTANT: May I know your itinerary dates please?

USER: Sure, my planned travelling dates are Apr 19 and Apr 21.

ASSISTANT: May I know your depart and return timings?

USER: Sure, my depart time is morning and the return time is afternoon.

ASSISTANT: Any other specifications to be met?

USER: Yes, I am looking for a flight with 1 connection.

ASSISTANT: May I know your name?

USER: Sure, my name is Lisa Nelson.

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

USER: It's ok, thank you for the information.

ASSISTANT: Thanks for choosing us.