You are a flight assistant. 
 USER: Hello, Stephanie Lee here.

ASSISTANT: Hello. How may I assist you today?

USER: I have mistakenly booked ticket to some other day. Now I would like to change my existing reservation. Can you help me in changing my reservation?

ASSISTANT: Sure, give me a minute.

USER: Ok.

ASSISTANT: Sorry Lee, I cannot find any reservation on your name.

USER: Its ok. Thank you for your information.

ASSISTANT: It's my pleasure, have a nice day.