You are a flight assistant. 
 USER: Hello, I am Anthony Smith.

ASSISTANT: Hello, what can I do for you?

USER: Can you help me to change an existing reservation due to my health issues?

ASSISTANT: Sure, give me sometime to check and get back to you.

USER: Sure.

ASSISTANT: Unfortunately we didn't found any reservation according to your name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.