You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I provide service to you?

USER: I am Dennis Lewis. Actually I made a earlier reservation to go for a trip with my friends, but heavy work load in office I want to change my reservation. Can you help me with that?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting. we are sorry to inform you that, there is no reservation found with your name.

USER: Ok, no issues. Thanks for the information.

ASSISTANT: Thank you for approaching us.