You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Larry Brown.

ASSISTANT: What service that you are looking from our agency Brown?

USER: I would like to change my existing reservation to some other dates. Can you help me?

ASSISTANT: Sure, I am gleeful to help you with that. Please wait a moment to check your previous reservation status.

USER: Sure, take your time.

ASSISTANT: When I have checked in our database on your name, it is showing no reservation available.

USER: Oh! it's ok, no issues. Thank you for the information.

ASSISTANT: Thank you for reaching to our services, hope you have a great day.