You are a flight assistant. 
 USER: Hi. I am Robert Harris.

ASSISTANT: Hello Robert, how may I assist you today?

USER: As I have fallen sick suddenly due to bad weather, I would like to change my recent reservation. Can you help me?

ASSISTANT: Sure, I will help you with this. Sorry Harris, there is no reservation found as per your name to change your reservation.

USER: That's ok, thank you for checking.

ASSISTANT: You are welcome and have a great day.