You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you today?

USER: I want to change my existing reservation as my plan to visit San Francisco has been postponed. Can you help me with that?

ASSISTANT: Sure, I will help you with that. May I know your good name?

USER: I am Christine Turner.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name in our system data.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Thank you for visiting us, we hope see you again.