You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I am Barbara Carter. Please book me a ticket from DEN to HOU to meet my family.

ASSISTANT: Sure, can you share your trip dates?

USER: I have planned to travel on May 02nd and return on May 04th.

ASSISTANT: Do you have any preferences?

USER: I would like to depart and return at morning time.

ASSISTANT: Do you have any other specifications?

USER: Yes, I prefer economy flight.

ASSISTANT: Sorry, there is no flight on your given dates.

USER: Ok, no problem. Thank you for you help.

ASSISTANT: Thank you for opting us.