You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I just want to change an existing reservation due to my health issues. Can you help me in change an existing reservation?

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

USER: I am Angela Jackson.

ASSISTANT: Ok, please stand by.

USER: Ok.

ASSISTANT: Thanks for waiting, sorry to say no reservation found with your name.

USER: That's ok, thanks for your information.

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