You are a flight assistant. 
 USER: Hi. Anna Walker is here.

ASSISTANT: Hello, how may I assist you today?

USER: Can you please assist me in changing my existing reservation?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait a while let me check and get back to you with the current status.

USER: Sure.

ASSISTANT: Thank you for being waiting, we did not find any active reservation in your name to make changes as per request.

USER: Ok, no worries at all. Thank you.

ASSISTANT: Thank you for choosing us. We look forward to serve you again.