You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Dennis Anderson, I want to change my reservation, as my reservation fare is more now I want a flight with low fare. Can you help me to change my reservation?

ASSISTANT: Sure, I will help you. Please wait for a while.

USER: Sure.

ASSISTANT: Sorry Dennis Anderson, no reservation found on your name.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for approaching us.