You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: Sure, may I know your name?

USER: Myself Barbara Campbell.

ASSISTANT: Sorry Barbara, no reservation is found by your name.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for contacting us.