You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Sure, I am happy to help you. Can you please let me know your good name?

USER: I am Jennifer Clark.

ASSISTANT: Sorry, we did not find any active reservation on your name in our records.

USER: That's ok, no issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.