You are a flight assistant. 
 USER: Hello. I am Stephen Smith.

ASSISTANT: Hello, how may I assist you?

USER: I had planned to go on a trip, but it was postponed due to some reasons. Can you change my recent reservation?

ASSISTANT: Ok. Sure, I will help you with that.

USER: Ok.

ASSISTANT: Thanks for waiting. But I am sorry to say that there is no flight reservation on your name to change it.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: Thank you.