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

ASSISTANT: Hello. How can I aid you?

USER: Can you please help me to change an existing reservation as my plan to meet my grand parents got postpone due to my health issues?

ASSISTANT: Sure, I can help you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: Myself Rachel Wilson.

ASSISTANT: Give me a minute.

USER: Ok.

ASSISTANT:  Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: No issue. Thank you for the information.

ASSISTANT: Thank you for opting us.