You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I need to change my recent reservation, can you help me in doing that?

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

USER: I am Dennis Davis.

ASSISTANT: Please wait a minute.

USER: Sure, take your time.

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

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you for contacting us.