You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Samuel Clark. I want to change an existing reservation, can you please help me in that?

ASSISTANT: Sure, I will help you. Please, wait a minute.

USER: Thank you. Sure, I will wait.

ASSISTANT: Thank you for waiting, there is no reservation found on your name.

USER: That's ok, not a problem. Thanks for your information.

ASSISTANT: Thank you for approaching us.