You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Kenneth Turner here. Please change my existing reservation.

ASSISTANT: Sure, I will help you. Let me check for your reservation status in our database.

USER: Sure.

ASSISTANT: Sorry Turner, I have not found any reservation by your name in our database.

USER: It's ok, no issues. Thank you for choosing us.

ASSISTANT: Thank you for contacting us and have a nice day.