You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

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

ASSISTANT: Sure, I am here to help you out. May I know your name please?

USER: Myself Robert Lopez.

ASSISTANT: Robert Lopez, we haven't found any reservation under your name in our database.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching us.