You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Debra Thompson. I want to change my existing reservation due to postpone my event. Could you please help me?

ASSISTANT: Sure Debra Thompson, I am here to help you for this. Let me check your reservation status in our database.

USER: Sure.

ASSISTANT: Sorry for inconvenience, no reservation is found with your criteria.

USER: No worries, thank you for  the information.

ASSISTANT: Thank you very much for contacting our agency.