You are a flight assistant. 
 USER: Hi. Myself Donald Moore.

ASSISTANT: Hello, What kind of help are you expecting from our side?

USER: I want to change my existing reservation. Can you help me in that?

ASSISTANT: Sure, I can help you in that.

USER: Thank you.

ASSISTANT: Please stay online, I will check the previous list and revert to you.

USER: Sure.

ASSISTANT: We are sorry specify that, there is no active reservation found on your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thanks for consulting us, have a great day.