You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you help me to book a normal cost flight ticket?

ASSISTANT: Sure, may I know your trip dates please?

USER: My travel dates are Sept 15 and Sept 17.

ASSISTANT: Can I know your airport codes please?

USER: My airport codes are LGA and IAH.

ASSISTANT: Do you have any other requirements?

USER: I would like to return back in the afternoon time.

ASSISTANT: Ok, let me know your name please.

USER: I am Samuel Young.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: No problem, thank you for the information.

ASSISTANT: My pleasure.