You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

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

ASSISTANT: Sure, give me a minute.

USER: Sure.

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

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching us.