You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: I would like to change my existing reservation due to postpone of my event. Could you please help me?

ASSISTANT: Sure, I will help you in changing the ticket. Sorry, there are no reservations found.

USER: I am Kathleen Gonzalez. No worries, thank you for your help.

ASSISTANT: Thank you for reaching us.