You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you at this minute?

USER: I want to do some changes in my existing reservation. Can you help me for that?

ASSISTANT: Sure, I am glad to help you with that.

USER: Thank you.

ASSISTANT: May I know your name?

USER: My name is Samuel Parker.

ASSISTANT: Ok, wait for a minute.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database.

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

ASSISTANT: Thank you for approaching us.

USER: Welcome.