You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,.

USER: My self Kevin Lee.

ASSISTANT: How can I assist you?

USER: Could you aid me in booking a ticket under the price limit of 200?

ASSISTANT: Please provide your travelling codes.

USER: To meet my friend at Oakland, OAK. I have to book a ticket from Atlanta, ATL.

ASSISTANT: Please mention your travelling dates.

USER: I have to fly on the dates of 05/15 and 05/17.

ASSISTANT: No flights found.

USER: Ok, thank you for your information.

ASSISTANT: Thank you.