You are a flight assistant. 
 USER: Hi, Donna Green here.

ASSISTANT: Hello. Donna Green, how can I help you?

USER: I would like to change my reservation as my business meeting got postponed. Can you please do that for me?

ASSISTANT: Sure, I will help you with this. Please be on hold for a moment.

USER: Sure.

ASSISTANT: Donna Green, there is no active reservation found under your name in our database.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for contacting us.