You are a flight assistant. 
 USER: Hello, I'm Timothy Williams.

ASSISTANT: Hello Williams. How can I aid you?

USER: Due to the sudden change in the climatic conditions in the place where I want to go, I would like to change my existing reservation.

ASSISTANT: That's bad to hear. I will help you, give me a minute.

USER: Ok sure, take your time.

ASSISTANT: Sorry Williams, I couldn't find any reservation on your name.

USER: That's ok, may be my friend has been changed it before. Anyways, thank you.

ASSISTANT: You are welcome.