You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Charles Robinson here.

ASSISTANT: Charles, how can I assist you?

USER: Could you book my ticket in a direct flight?

ASSISTANT: Sure, I will help you. May I know your source and destination airport codes?

USER: I will take-off from OAK and land at CLT.

ASSISTANT: Ok, may I know your travel dates?

USER: My itinerary dates are 10/08 and 10/10.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry Charles, there is no direct flight available on your preferred dates.

USER: No problem, thank you for checking.

ASSISTANT: You are welcome and thank you for choosing us.