You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you now?

USER: I am Robert Turner. I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, I will help you to change your reservation. Please wait for a moment, while I check for reservation.

USER: Sure.

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

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for visiting us, we hope see you again.