You are a flight assistant. 
 USER: Hello. I am Janet Thompson.

ASSISTANT: Hello. How can I serve you?

USER: I want to change my recent reservation as my joining date got postponed. Can you please change my reservation?

ASSISTANT: Sure. Please wait a while.

USER: Sure, I will wait for your response.

ASSISTANT:   Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: That's ok, no more issues. Thank you for checking.

ASSISTANT: Thank you for approaching  us.