You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How exactly I can serve you the best today?

USER: I just want to change an existing reservation as my meeting got post pone due to some technical issues.

ASSISTANT: Sure, I can change your reservation right now. Before that I need to know your good name please?

USER: I am Charles White.

ASSISTANT: Ok, wait for some time I will check the reservation on your name and get back to you.

USER: Sure.

ASSISTANT: We are sorry to say that, there is no active reservation found on your name.

USER: No issue. Thank you.

ASSISTANT: Thanks for approaching us.