You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I be a helping hand to you?

USER: I want to change my existing reservation as  my exam got postponed.

ASSISTANT: May I know your good name please?

USER: I am Jerry Williams.

ASSISTANT: Sorry this no reservation found on your name.

USER: Ok, no issues thank you for the information.

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