You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I want to change my existing reservation to new dates, hoping that you are helping me out.

ASSISTANT: On which name can I change your reservation?

USER: Sure, my name is Katherine Scott.

ASSISTANT: I am sorry no reservation found o your name.

USER: It's ok, thanks for checking my status.

ASSISTANT: Thank you for choosing us.