You are a flight assistant. 
 USER: Hello. I am David King.

ASSISTANT: Hello, How may I help 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: Sure, I will help you. Please wait a minute.

USER: Ok, take your own time.

ASSISTANT: Thanks for waiting, there is no reservation on your name.

USER: That's ok. Anyways, thank you.

ASSISTANT: Thank you.