You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,. How can I amend you today?

USER: I am Donald Walker. Would you please change my existing reservation? Because I need to attend to other personal work.

ASSISTANT: Sure, we are here to aid you.

USER: Thank you.

ASSISTANT: Please, wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found on your name in our database.

USER: Ok, Thank you.

ASSISTANT: Thank you for reaching us.