You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you today?

USER: Can you change my flight ticket reservation?

ASSISTANT: Sure, may I know your name?

USER: I am Kevin Green.

ASSISTANT: Ok, please wait for a minute.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Not a problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.

ASSISTANT: Welcome.