You are a flight assistant. 
 USER: Hello. I am Gregory Jones.

ASSISTANT: Hello, how can I help you today?

USER: I planned to meet my cousin in ATL, can you please help me to book a flight ticket from IAH?

ASSISTANT: Sure, may I know your planned travel dates?

USER: I prefer to travel on May 17 and May 19.

ASSISTANT: Do you have any specifications?

USER: I would like to return back in evening.

ASSISTANT: Is there any class preference for you?

USER: No.

ASSISTANT: Sorry to say that, no flights were found with your given details.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your help.