You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Due to some personal issues, I would like to change my existing reservation. Please help me out.

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: My name is Lisa Hill.

ASSISTANT: Ok, wait a minute please.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting, sorry to inform no reservation found on your name.

USER: Ok, no problem. Thank you for your information.

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