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

ASSISTANT: Hello. How can I aid you?

USER: I want to do a research on a project in Space Center Houston, can you please book me a flight ticket?

ASSISTANT: Sure. Can I know your travelling dates?

USER: My travelling dates are from 08/10 to 08/12.

ASSISTANT: Please share me your airport codes.

USER: I want to fly from Denver, CO-DEN to Houston, TX-HOU.

ASSISTANT: Thank you for waiting, sorry to inform you that unfortunately there is no flights available by the given details.

USER: Ok, no problem. I will try with other alternative.

ASSISTANT: Thank you.

USER: Thank you.