You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Could you please change my existing reservation due to postpone of my client meeting?

ASSISTANT: Sure, I am here to help you for this. May I know your name please?

USER: My name is Pamela Nelson.

ASSISTANT: Just a moment, let me check your reservation status in our database.

USER: Ok, take your time.

ASSISTANT: Sorry for inconvenience, no reservation is found with your criteria.

USER: Not an issue, thank you for checking.

ASSISTANT: Thank you very much for reaching us.