You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to change my existing reservation due to sudden postpone of my family trip dates. Can you help  me in doing that?

ASSISTANT: Yes, can you share me your name for checking?

USER: Sure, I am Debra Green.

ASSISTANT: Give me a moment.

USER: Sure.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: Ok, no problem. Thank you for your help.

ASSISTANT: Thank you for contacting us.