You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Samuel Johnson. Please book a flight ticket from IAH to MCO.

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

USER: 07/27 and 07/29 are my travelling dates.

ASSISTANT: Do you have any other requirements?

USER: Both depart and return time should be at evening and want a connecting flight.

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

USER: That's ok, no problem. Thank you.

ASSISTANT: Most welcome.