You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

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

ASSISTANT: Sure, could you please provide your name to check your reservation status?

USER: Myself Helen Perez.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to say, no details were found regarding your reservation in my database.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for choosing us, have a nice day.