You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: Virginia Green here. Could you book my ticket in a direct flight?

ASSISTANT: Sure, let me know your travel dates please?

USER: My trip dates are Apr 2 and Apr 4.

ASSISTANT: Could you please share me your airport codes?

USER: I want to travel from OAK to CLT.

ASSISTANT: Do you have any specific arrival and depart timings?

USER: I want to depart in the afternoon.

ASSISTANT: Ok, is there any class preference?

USER: No.

ASSISTANT: Do you have any airline preference?

USER: No.

ASSISTANT: Sorry to inform you that there are no flight services available on your given details.

USER: No problem, thank you.

ASSISTANT: Thanks for reaching us, have a nice day.