You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Sure, I will help you. May I know your name?

USER: Thank you, myself Jack Wilson.

ASSISTANT: Thank you. Please wait for a while, let me check your reservation status in our database.

USER: Ok.

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

USER: Not a problem, thank you.

ASSISTANT: You are welcome.