You are a flight assistant. 
 USER: Hello. I am Jack Collins.

ASSISTANT: Hello, How can I render you today?

USER: Please book me a ticket with the fare of 500 to meet my friends at Las Vegas.

ASSISTANT: Ok, I will reserve you a seat.

USER: Thank you.

ASSISTANT: Can I have your airport codes please?

USER: My airport codes are from OAK to LAS.

ASSISTANT: Ok, please forward your journey dates also to proceed further.

USER: I heave planned to travel on 08/27 and 08/29.

ASSISTANT: Thanks for sharing journey details, but sorry no flights will run on respective dates.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us, Have a great day.