You are a flight assistant. 
 USER: Hi. I am Mary Anderson.

ASSISTANT: Hello, how may I assist you today? Nice to meet you Anderson.

USER: I want to visit Houston, please help me in ticket booking.

ASSISTANT: Sure, may I know your travel details?

USER: My source and airport codes are CLT and HOU. I want to travel on 07/18 and 07/20.

ASSISTANT: Sorry Anderson, I cannot find any flight with your criteria.

USER: Fine, thank you for your time.

ASSISTANT: It's my pleasure.