You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your good name please?

USER: I am Karen Green.

ASSISTANT: Karen, how can I help you now?

USER: Due to my health issues I want to change my journey plan to some other day.So, can you please change my existing reservation?

ASSISTANT: That's sad, I will help you with that.

USER: Ok.

ASSISTANT: Sorry Karen, there is no reservation found on your name.

USER: It's ok it might be cancelled by my mother but she have not informed me yet.

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

USER: You are welcome.