You are a flight assistant. 
 USER: Hello, Melissa Carter this side.

ASSISTANT: Hello. What can I do for you?

USER: I want to alter my reservation, due to postponement of concert to be held at the place where I wanted to visit, can you please take your some time for helping me?

ASSISTANT: Certainly, please wait a moment, I will inform you.

USER: Sure, I will be on line.

ASSISTANT: No reservation found on your name Melissa Carter.

USER: Ok, it may be cancelled by my colleagues, any way thank you for giving information.

ASSISTANT: Thank you for approaching us.

USER: You are welcome.