You are a flight assistant. 
 USER: Hi. I am Mark Edwards.

ASSISTANT: Hello, how may I oblige you today?

USER: Will you help me in booking a flight from Philadelphia, PHL?

ASSISTANT: Sure, I am gleeful to assist you.

USER: Thank you.

ASSISTANT: May I know on what dates you prefer to travel?

USER: 03/27-03/29 are the travelling dates.

ASSISTANT: Could I have your destination airport code please?

USER: As I have to give a seminar in Houston University, I planned to travel to Houston, HOU.

ASSISTANT: Ok, please wait a moment, let me search a flight for you.

USER: Sure.

ASSISTANT: Sorry to say this, no flights will run on that particular location due to tornado alert.

USER: Ok. Thank you.

ASSISTANT: Thank you for choosing us, hope to serve you better next time.