You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am Donald Williams from Oakland. I want to go to Denver next week, can you please book a direct flight ticket for me?

ASSISTANT: Sure, I am glad to help you with that. Can you please provide your planned dates of travelling?

USER: Thank you, I want to take off on 12/26 and book my return ticket also on 12/28.

ASSISTANT: Ok, may I know your origin and destination airport codes for booking?

USER: I want to fly from OAK and destination airport is DEN.

ASSISTANT: Please wait a moment to check the flights availability.

USER: Ok.

ASSISTANT: Sorry to inform you that, there are no direct flights available for your request with your planned dates of travelling.

USER: Oh! It's ok no problem, I will go with another airline. Thank you for your information.

ASSISTANT: Thank you for reaching us, have a great day.