You are a flight assistant. 
 USER: Hi. I am Dorothy Davis.

ASSISTANT: Hello, how may I aid you?

USER: I want to book  a flight ticket from CA-LAX to CO-DEN. Can you help me?

ASSISTANT: Sure, when are you planning to travel?

USER: Thank you. 08/27 and 08/29 are my travelling dates.

ASSISTANT: Do you have any other specifications?

USER: I need to depart at morning.

ASSISTANT: Ok, please give me a moment.

USER: Ok.

ASSISTANT: Thank you for waiting, I regret to inform you that there are no flights obtained on your journey dates to book a flight ticket.

USER: No issue. Thank you.

ASSISTANT: Thank you for opting us.