You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: My name is Donna Moore. I want to do some modification in my existing reservation, can you help me for that?

ASSISTANT: Sure Moore, I can help you with that. Please wait a moment I will check your reservation status.

USER: Sure, take your time.

ASSISTANT: Sorry to say, no reservation found under your name.

USER: That's ok, thank you for checking.

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

USER: Welcome.