You are a flight assistant. 
 USER: Hello,. I am Melissa Hill.

ASSISTANT: Hello, how may I assist you today?

USER: I made a earlier reservation to attend a conference, due to some security issues it got postponed. Can you please change my existing reservation?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: Thanks for waiting, no active reservation was found on your name in the database.

USER: Ok, no issue. Thank you.

ASSISTANT: Thank you for opting us.