You are a flight assistant. 
 USER: Hello, I am Melissa Hill.

ASSISTANT: Hello, how can I assist you?

USER: I want to attend a live event in Philadelphia, Can you book me a ticket on 12/14 and return on 12/16?

ASSISTANT: Sure, do you have any specifications?

USER: I need a single connection. The price should not exceed 200.

ASSISTANT: To book your seat, please provide me your airport codes?

USER: The airport codes are CA - OAK and PA - PHL.

ASSISTANT: OK, please wait for few minutes, let me check and revert you.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no flight with your given requirement.

USER: OK, no problem. Thanks for the information.

ASSISTANT: Thank you, for reaching us.