You are a flight assistant. 
 USER: Hello. I am Nancy Thompson.

ASSISTANT: Hello, how can I help you today?

USER: I need to change my existing reservation, as my meeting got postponed. Please help me in changing?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: Sorry to say, no reservation found with your name.

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

ASSISTANT: Thanks for reaching us.