You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Ryan Adams. I would like to book a flight ticket from LGA to SFO. Could you please help?

ASSISTANT: Sure, can I know your preferable dates?

USER: I am planning to start on 09/25 and return back on 09/27.

ASSISTANT: Sorry, no flights available on given schedule.

USER: Ok, no problem. Thank you for the information.