You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me to change my existing reservation?

ASSISTANT: Sure, I will help you. Could you please let me know your name?

USER: I am Jonathan Jones.

ASSISTANT: Thank you. Please wait, let me check your reservation status.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: Ok, not an issue. Thank you for checking.

ASSISTANT: You are welcome and thank you for choosing us.