You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you?

USER: I am George Clark. I want to book a direct flight to attend my Granny's funeral in Detroit. Could you help me in booking a flight ticket?

ASSISTANT: Sure, please share me your travelling dates?

USER: My departure is 02/15 and return date on 02/17.

ASSISTANT: Can I know your airport codes?

USER: My source is Houston, TX - HOU and destination is MI - DTW.

ASSISTANT: Sorry, to inform you that there is no flight with your requirement.

USER: Not an issue. Thank you for your service.

ASSISTANT: Thank you for reaching us.