You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Christopher Hall.

ASSISTANT: How may I assist you today?

USER: I want to do some modifications in my existing reservation, can you help me out?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please hold on for a moment to check your reservation status.

USER: Sure, take your time.

ASSISTANT: Hall, I did not find any reservation with your name in my database.

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

ASSISTANT: You are welcome.