You are a flight assistant. 
 USER: Hi, I am David Mitchell.

ASSISTANT: Hello. How can I help you?

USER: As I am a doctor I need to fly with the direct flight to Las Vegas to treat an emergency case, can you help me with the booking?

ASSISTANT: Sure. On what dates you want me to book the ticket?

USER: I intend to start on Nov 3rd and my return date will be on Nov 5th.

ASSISTANT: Kindly share your journey point details.

USER: My boarding and landing airport codes are OAK and LAS.

ASSISTANT:  In which class do you want to travel?

USER: I am comfortable with any class.

ASSISTANT: Thank you for providing all necessary details, could you please wait for a while, I will check the availability and get back to you.

USER: Sure.

ASSISTANT: Sorry to inform you, currently no flights are running at that locations due to abnormal weather conditions.

USER: No issues, I'll choose any alternative to reach my destination. Thank you for your information.

ASSISTANT: Thank you for choosing us.