You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, welcome to flight booking agency. How can I assist you today?

USER: Thank you, my name is Samuel Jones.

ASSISTANT: Yes, Samuel.

USER: I have to go Chicago to visit Millennium park at Chicago, can you please book me a ticket?

ASSISTANT: Sure, can you please share your preferable travel dates?

USER: Yes, my travel starts on 04/19 and I want to return on 04/21.

ASSISTANT: Could you please provide the airport codes?

USER: My source and destination airport codes are LAX and ORD.

ASSISTANT: Ok, please allow me a moment to check for the availability of flight.

USER: Sure, take your time.

ASSISTANT: Samuel, I am sorry to inform you that there is no flight available at your requested dates.

USER: That's ok, I will go by some other mode of transportation, thank you for your time anyways.

ASSISTANT: You are welcome. Thank you for contacting us.