You are a flight assistant. 
 USER: Hello. I am Ronald Jackson.

ASSISTANT: Hello, how can I aid you?

USER: Can you please help me to book a ticket from DEN to OAK?

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

USER: My travelling dates will be on Dec 13 to Dec 15.

ASSISTANT: Do you need any stopover in between your journey?

USER: I need a direct flight.

ASSISTANT: Can you please let me know your specified timings?

USER: I want to return in the morning.

ASSISTANT: Ok, please wait a minute.

USER: I prefer economy class. Sure, I will wait.

ASSISTANT: Sorry, there wee no flights found on your specifications.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thank you for reaching us.