You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: Actually, I want to change my reservation which is done recently due to some health issues, can you please help me out?

ASSISTANT: Sure, may I know your name?

USER: Sure, my name is Paul Wilson.

ASSISTANT: Ok, please wait a minute.

USER: Sure, I will wait.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Ok, that's fine. Thank you for your service.

ASSISTANT: Thank you for choosing us.