You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Andrew Perez.

ASSISTANT: Ok, what can I do for you Perez?

USER: I would like to present a seminar in University located at San Francisco, Ca - SFO. Can you please book a ticket with a price limit of 200?

ASSISTANT: Sure, may I know your travelling dates?

USER: My planned journey dates are 01/18 and 01/20.

ASSISTANT: May I know your lay by's?

USER: I need a lay by. My source point is Chicago, IL - ORD.

ASSISTANT:  May I know your source code? Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no flights found on your requested dates.

USER: Ok, no issue. Thanks for your response.

ASSISTANT: Thank you for approaching us.