You are a flight assistant. 
 USER: Hello, Richard Hernandez here.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation, due to heavy snowfall in Chicago. Could you help me out?

ASSISTANT: Sure Richard. Please give me a moment, I will check for the status of your reservation.

USER: Sure.

ASSISTANT: Please provide me your airport codes for your existing reservation.

USER: My origin and destination airport codes are ORD and SFO.

ASSISTANT: May I know your preferred journey dates please?

USER: My itinerary dates are 11/16 and 11/18.

ASSISTANT: Richard, based on your details I found a flight with price 100. Shall I book the ticket for you?

USER: Please confirm my ticket.

ASSISTANT: Your ticket is confirmed with Southwest airlines and the flight number is 1002.

USER: Thank you for assisting me.

ASSISTANT: Thank you for choosing our services.