You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want t o change my existing reservation so, can you please help me with this?

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

USER: My name is Gary Anderson.

ASSISTANT: Wait a minute please.

USER: Ok.

ASSISTANT: Thank you for waiting, sorry no reservation found with your name.

USER: No problem, thank you.

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