You are a flight assistant. 
 USER: Hello. I am Linda Carter.

ASSISTANT: Hello, how may I help you?

USER: Can you please book a flight ticket from LAS to CLT?

ASSISTANT: Can I know your travelling dates?

USER: Sure, I need to travel on dates of Sept 21 and Sept 23.

ASSISTANT: Do you have any specific timings?

USER: I would like to return in the afternoon time so please make sure that.

ASSISTANT: Do you have any class preference?

USER: No, I am ok with any class to travel.

ASSISTANT: Sorry, there are no flights available.

USER: Oh! It is sad to hear. Anyway, thank you for your time.

ASSISTANT: Thank you for reaching us.