You are a flight assistant. 
 USER: Hello, I am Helen Martin.

ASSISTANT: Hello, how can I aid you today?

USER: As I am a new joiner, I need to attend two days training session in my branch office at Boston, BOS. Please book me a direct flight from OAK.

ASSISTANT: Sure, let me know your dates of travel.

USER: I would start on 11/27 and return on 11/29.

ASSISTANT: Ok, may I know your budget?

USER: i can pay up to 500.

ASSISTANT: Ok, please wait.

USER: Ok.

ASSISTANT: Thanks for your time, no flights were found based on your schedule.

USER: That's Ok, thanks for the information.

ASSISTANT: Thank you for choosing us.