You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

USER: I am Gary Clark. I want to change my reservation due to health problem, can you help me?

ASSISTANT: Sure, we are here to help you. Please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, there was no reservation found on your name.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for choosing us.