You are a flight assistant. 
 USER: Hi. Donald Collins here.

ASSISTANT: Hello Donald, how can I assist you?

USER: Las Vegas is one of the most populous city in the United states and I am planning to own a house there. So I will visit Las Vegas on 04/23 from LAS.

ASSISTANT: Ok Donald, can I know your destination code please?

USER: It is a round trip so I will be ending my journey at LAS and my start date will be 04/21.

ASSISTANT: Thank you Donald for providing your journey details, please wait while I check?

USER: Ok, ensure that It is a connecting flight.

ASSISTANT: There is a flight available with 1 connection and the airline is UA. Do you want me to proceed with the booking process?

USER: Sure, you can proceed for the booking.

ASSISTANT: Donald the booking is confirmed and the flight number is 1007.

USER: Ok, thanks for your assistance.

ASSISTANT: Your welcome.