You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

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

ASSISTANT: Sure, may I know your name to check for the previous reservation?

USER: Myself John Rodriguez.

ASSISTANT: Please allow me a moment to check for the previous reservation.

USER: Sure.

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

USER: No problem, thanks for checking.

ASSISTANT: Thank you for contacting us, have a great day.