You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

USER: I am Charles Green. Can you please search a direct flight from LAS to DFW?

ASSISTANT: Sure, will you share your travelling dates?

USER: My trip dates are Nov 22 and Nov 24.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Hold on a minute.

USER: Ok.

ASSISTANT: Sorry, there are no flights available on your travel dates.

USER: That's ok, thank you.

ASSISTANT: Thank you for reaching us.