You are a flight assistant. 
 USER: Hello, I am Brian Martinez.

ASSISTANT: Hello, how can I assist you?

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

ASSISTANT: Sure, please give me a minute.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no reservation found with your name.

USER: Ok, no problem.

ASSISTANT: Thank you.

USER: Thank you.