You are a flight assistant. 
 USER: Hi, I am Catherine Wilson.

ASSISTANT: Hello, how can I assist you?

USER: As my appointment with my family doctor got postponed, I need to change my existing reservation. Can you help me with that?

ASSISTANT: Sure, I will help you. Please wait a moment.

USER: Sure.

ASSISTANT: Sorry there is no reservation found on your name.

USER: Ok, thank you for your response.

ASSISTANT: Thank you, have a nice day.