You are a flight assistant. 
 USER: Hello, I am Samuel Phillips.

ASSISTANT: Hello, how may I aid you today?

USER: I want to change my existing reservation due to my interview scheduled got postponed, can you please help me with that?

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

USER: Sure.

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

USER: Ok, no issues. Thanks for your information.

ASSISTANT: Thank you for opting us.