You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I serve you?

USER: I would like to change my existing reservation as my appointment with my lawyer got postponed. Can you help me with that?

ASSISTANT: Sure, we are glad to help you out. May I know your good name?

USER: Sure, I am Nicholas Anderson.

ASSISTANT: Thanks for providing me your information. We didn't found any reservation by this name.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for choosing us.