You are a flight assistant. 
 USER: Hello. I am Margaret Parker.

ASSISTANT: Hello, how may I support you today?

USER:  I want to change my reservation due to prepone of my meeting.

ASSISTANT: Sure, we are blissful to serve you. Please hold a moment, let me check your recent reservation and let you know.

USER: Ok.

ASSISTANT: Thanks for your valuable time, unfortunately no reservation found with provided name.

USER:  Ok, thank you for your response.

ASSISTANT: Thank you for approaching us, have a great day ahead.