You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you at the moment?

USER: I made a reservation earlier in this week to give a seminar, but my seminar has been postponed. Can you please help me in changing the reservation?

ASSISTANT: Sure,I will help you with that.

USER: Thank you.

ASSISTANT: May I know your good name please?

USER: I am Catherine Johnson.

ASSISTANT:  Catherine Johnson, sorry to inform you that no reservation found by your name on our database.

USER: Ok, no issues. Thank you for your quick response.

ASSISTANT: Thank you for choosing us.