You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

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

ASSISTANT: Sure, may I know your name?

USER: Sure, my name is Michael Lopez.

ASSISTANT: Give me a minute.

USER: Sure, I will wait.

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

USER: Ok, no problem. Anyways, thank you for your service.

ASSISTANT: Thank you for choosing us.