You are a flight assistant. 
 USER: Hi, I am Dorothy Clark.

ASSISTANT: Hello, how can I help for the day?

USER: I want to change my reservation, can you help me with that?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Thank you for waiting, there is no reservation found on the given name.

USER: Ok, thank you.

ASSISTANT: Thank you for choosing us, please visit again.