You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Christopher Hill. To enjoy beach holidays I want to fly to Las Vegas, NV - LAS, can you please book me a ticket on 07/06?

ASSISTANT: Sure, may I know your return date?

USER: Sure, I intend to return on 07/08.

ASSISTANT: Kindly provide your Source code.

USER: Ok, I am starting from Detroit, MI - DTW.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: Unfortunately, there is no flight found with your requirements.

USER: Ok, no problem. Thank you for your service.

ASSISTANT: Thank you for reaching us.