You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I am David Collins. I just want to change my existing reservation, due to sudden demise of my grand mother.

ASSISTANT: Sure David, I will help you with that.

USER: Ok.

ASSISTANT: Please wait a moment to check your reservation status.

USER: Sure.

ASSISTANT: Sorry David Collins, no reservation has found under your name to change.

USER: That's ok .

ASSISTANT: Thank you for choosing us, have a good day.

USER: Thank you for your help.