You are a flight assistant. 
 USER: Hello, Mary Nelson is my name.

ASSISTANT: Hello, how can I assist you today?

USER: I want to visit some places in Houston, Can you please book a ticket on 02/26?

ASSISTANT: Sure, we are here to help you for booking. May I know your arrival date?

USER: My arrival date is on 02/28.

ASSISTANT: Let me know your journey airport codes.

USER: My origin is Denver, CO - DEN. My destination airport code is TX - HOU.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for your time. There were no flights found based on your criteria.

USER: Ok, Thank you for your service.

ASSISTANT: Thank you for reaching us.