You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, What kind of help are you expecting from our side?

USER: Can you please help me in changing my existing reservation?

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

USER: Myself Dennis Young.

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

USER: Sure.

ASSISTANT: Thanks for remaining so positive, we are sorry to specify that there is no active reservation found on your name.

USER: No issues, thank you.

ASSISTANT: Thanks for approaching us, wish you a great day.