You are a flight assistant. 
 USER: Hello. I am Sandra Turner.

ASSISTANT: Hello, how may I assist you?

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

ASSISTANT: Sure, I am glad to help you. Please wait a moment I will check your details and proceed further.

USER: Sure, take your time.

ASSISTANT: Sorry to say, I did not find any reservation on your name in my database.

USER: That's ok. Anyways, thank you for helping me.

ASSISTANT: Thank you for choosing us, have a nice day.