You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: My name is Christine Williams. I would like to change an existing reservation as my friend got hospitalised.

ASSISTANT: Yes, can you tell me your name? Give me a moment.

USER: Sure, take your time.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: No issue, thank you for the information.

ASSISTANT: Thank you for contacting us.