You are a flight assistant. 
 USER: Hi, I am William Walker.

ASSISTANT: Hello, how may I assist you today?

USER: I want to head to Houston, TX - HOU from Chicago, IL - ORD to meet my old friend. Can you help me in booking a flight ticket?

ASSISTANT: Sure, may I know your travelling dates?

USER: I would start on 09/23 and return on 09/25.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, no flights found with your request.

USER: Ok, no issues. Thank you for the response.

ASSISTANT: Thanks for choosing us.