You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: Can you please help me to search a flight from the airport Houston to Phoenix?

ASSISTANT: Sure, I am happy to help you with that. Can I know your travelling dates?

USER: Thank you. The preferable travel dates are July 05 and July 07.

ASSISTANT: Ok, may I know your airport codes?

USER: The origin and destination airport codes are HOU and PHX.

ASSISTANT: Ok, may I know your requirements?

USER: Yes, I am willing to travel in an economy class flight. So, please search for that.

ASSISTANT: Can I know your name?

USER: My name is Melissa Hill.

ASSISTANT: Ok, wait for a minute.

USER: Ok, take your time.

ASSISTANT: Sorry to say that, there are no flight's available based on your journey details.

USER: It's ok, not a problem with that. Anyways thank you for your time.

ASSISTANT: Thank you for reaching us.

USER: You are welcome.