You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: I am Matthew Smith.

ASSISTANT: Ok.

USER: Due to my health problem I want to change my reservation, can you please help me in that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Sorry, no reservation found with your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for opting us.