You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how best I can serve you at this moment?

USER: I want to change my existing reservation due to my health issues, can you please help me with this?

ASSISTANT: Sure, we are here to help you.

USER: Ok.

ASSISTANT: May I know your name please?

USER: I am Justin Campbell.

ASSISTANT: Ok, please be on hold for some time.

USER: Ok.

ASSISTANT: Sorry, we could not find any reservation on your name.

USER: It's ok, thank you for checking.

ASSISTANT: Thank you for opting us.