You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How could I help you today?

USER: Can you please help me to change my reservation as I have postponed my trip?

ASSISTANT: Sure, I am here to help you with that.

USER: Thank you.

ASSISTANT: Can I know your good name please?

USER: My name is William Evans.

ASSISTANT: Please give me a moment.

USER: Sure.

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

USER: Not an issue, thank you for your time.

ASSISTANT: Thank you for choosing us.