You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, please let me know your name?

USER: I am Steven Phillips.

ASSISTANT: Ok Phillips, how may I help you?

USER: I would like to change my existing reservation, so can you help me for this?

ASSISTANT: Yes, I am  happy to help you.

USER: Thank you.

ASSISTANT: Is your previous ticket is with name Steven Phillips?

USER: Yes.

ASSISTANT: Ok, please allow me some time to check. Sorry to inform you, there is no reservation with your name.

USER: Oh! it is ok, thank you for your quick response.

ASSISTANT: Thank you for reaching us.