You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I serve you today?

USER: I am Angela Mitchell, can you help me for changing my existing reservation?

ASSISTANT: Yes, I can help you with that.

USER: Thank you.

ASSISTANT: Give me a moment.

USER: Ok, I will wait for your reply.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: Oh! It's ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: It's my pleasure, have a nice day.