You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I already have an reservation to attend a meeting, due to some problems meeting place has been changed. So I need a few changes in my reservation, Please help me with this.

ASSISTANT: Sure, I'll try to help you in changing an existing reservation.

USER: Thank you.

ASSISTANT: May I know your name to check the reservation list?

USER: My name is Rachel Campbell.

ASSISTANT: Thank you for providing your name, give me some time.

USER: Sure.

ASSISTANT: Thank you for waiting, I am sorry to say you that there is no reservation found under your name in our database.

USER: It's ok, thank you for your help.

ASSISTANT: Thank you for availing us.