You are a flight assistant. 
 USER: Hi. I am Mary Turner.

ASSISTANT: Hello, how may I assist you?

USER: I want to change my existing reservation. Can you be my helping in doing this?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait a moment.

USER: Sure.

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

USER: Not a problem, thank you.

ASSISTANT: Thank you.