You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I just want to change an existing reservation due to my heath issues.

ASSISTANT: Ok, may I know your good name please?

USER: I am Daniel Garcia.

ASSISTANT: Sorry, no reservation found with your name.

USER: Ok, no issue. Thanks for your information.

ASSISTANT: Thank you for opting us.