You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how could I help you today?

USER: My name is Deborah Harris. I want to change my existing reservation due to postpone of my client meeting.

ASSISTANT: Please give me a moment, let me check and revert to you.

USER: Sure.

ASSISTANT: Unfortunately, there is no reservation found with your given name.

USER: Not an issue, thank you.

ASSISTANT: Thank you for choosing us.