You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I am planning to book a ticket to attend a meeting at ORD. Can you please help  me out from LGA?

ASSISTANT: May I know on what dates would you like to travel?

USER: I would like to travel on Sept 21 and return back on Sept 23.

ASSISTANT: Do you prefer any specifications?

USER: Yes, my depart time should be afternoon.

ASSISTANT: May I know your name?

USER: My name is Elizabeth Parker.

ASSISTANT: Sorry to inform you that unfortunately there is no flights available by the given details.

USER: That's fine, thank you for your help.

ASSISTANT: Thank you.