You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I would like to change my existing reservation as my appointment with doctor got postponed. Can you help me update my reservation which was made on the name of Linda Williams?

ASSISTANT: Sure, please give me a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found under your name.

USER: That's fine, thanks for your information.

ASSISTANT: Welcome, have a great day.