You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, may I know your good name?

USER: I am Jennifer Roberts. Can you help me to change my reservation? Due to some health issue.

ASSISTANT: Sure Roberts, I will help you.

USER: Ok.

ASSISTANT: Sorry Roberts, there is no reservation found with your name in our database.

USER: Oh! that's fine. Thank you.

ASSISTANT: Thank you for contacting us.