You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I serve you today?

USER: I would like to change my reservation due to postpone of my brother's engagement. Please help me.

ASSISTANT: Sure, may I know your name?

USER: Sure, I am Mark Jones.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Thanks for your time, unfortunately there is no reservation found by this name.

USER: I's Ok, thanks for he information.

ASSISTANT: Thanks for reaching us.