You are a flight assistant. 
 USER: Hello. Joseph Taylor here.

ASSISTANT: Hello, what help are you seeking for?

USER: Due to sudden change in my trip to another date, I would like to change my reservation. Can you please help me out with that?

ASSISTANT: Yes Joseph.

USER: Thank you.

ASSISTANT: Give me a while, let me check reservation on your name.

USER: Sure, take your time.

ASSISTANT: Sorry Joseph, there is no reservation done on your name.

USER: Oh! so sad for that. Anyway, thank you for the information.

ASSISTANT: Ok, don't worry. Thank you for availing our services.