You are a flight assistant. 
 USER: Hi. I am Rebecca Phillips.

ASSISTANT: Hello, how may I help you today?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Sure. Wait a minute.

USER: Thank you. Ok, I will wait.

ASSISTANT: Sorry, we could no find any reservation on your name.

USER: Not a problem, thank you.

ASSISTANT: Thank you for reaching us.