You are a flight assistant. 
 USER: Hello. I am Frank Lewis.

ASSISTANT: Hello, how can I support you today?

USER: I need to change my existing reservation, Can you please help me that?

ASSISTANT: Sure, I will help you with that. Please wait for a moment, while I search for the reservation.

USER: Sure.

ASSISTANT: Thanks for waiting, Sorry to inform you there is no any reservation found on your name.

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

ASSISTANT: Thank you for reaching us.