You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I just want to change my recent reservation because my business trip postponed, can you help me for that?

ASSISTANT: Yes, I am here to help you. May I know your name for searching?

USER: I am Robert Parker.

ASSISTANT:  Robert Parker, wait a moment.

USER: Sure.

ASSISTANT: Sorry  Robert, there is no ticket found in our data base on your requested name.

USER: It's ok. Thanks for helping me.

ASSISTANT: Thank you for contacting us Robert Parker.