You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Sure, please share your good name?

USER: My name is Gregory Johnson.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for your time, sorry no reservation found on your name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for choosing us.