You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I want to change dates in my existing reservation, can you please help me?

ASSISTANT: Sure, may I know the name to check for the status?

USER: Myself Daniel Green.

ASSISTANT: Sorry, there is no active reservation has been found under your name in our database to amend it.

USER: No issue, anyway thank you for checking.

ASSISTANT: Thank you for reaching us.