You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I need to change my reservation due to my planned event got postponed. So please help me with that.

ASSISTANT: Sure, I will help you in change of flight ticket reservation?

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Sure, please check the reservation with my name Sandra Allen.

ASSISTANT: Wait for a moment please.

USER: Sure, take your time.

ASSISTANT: Thanks for waiting.

USER: It's ok.

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

USER: Oh! It may not be booked properly while booking. I will check my mail once again and revert you back.

ASSISTANT: Thank you.

USER: Anyway, thank you for your time.