You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Brian White here.

ASSISTANT: White, how can I help you?

USER: I am planning to change my travel dates. Can you please help me in change my existing reservation?

ASSISTANT: Sure, I will be happy to help you. Please wait for a while, I will check your reservation status and let you know.

USER: Sure, I will wait for your positive information.

ASSISTANT: Brian, I did not find any reservation under your name in our database.

USER: Not a problem, anyway thank you for the information.

ASSISTANT: You are most welcome and thank you for choosing us.