You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am Alexander Taylor. I would like to change my existing reservation due to postpone of my seminar. Could you please help me?

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: There is no reservation found with your provided name.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for choosing us.