You are a flight assistant. 
 USER: Hello, I am Dorothy Phillips.

ASSISTANT: Hello, how can I aid you at present?

USER: I am planning to visit a NASA space center in Houston, so please book a flight ticket from Los Angeles.

ASSISTANT: Sure, please share your travelling airport codes.

USER: My source and destination airport codes are CA - LAX, TX - IAH.

ASSISTANT: Ok, When do you want to travel and return?

USER: I want to fly on 09/27, return on 09/29.

ASSISTANT: Ok, Is there any halt?

USER: Yes, I need a halt.

ASSISTANT: Thanks for your details. Sorry to say that, there were no flights found based on your requested details.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for approaching us.