You are a flight assistant. 
 USER: Hello, Brenda Edwards here.

ASSISTANT: Hello. Welcome to Google airline agency. How can I assist you today?

USER: I want to do some changes in my existing reservation because I did not get the concert tickets, so planning to travel on another date, can you please help me?

ASSISTANT: Sure, please give me a moment.

USER: Ok, take your time.

ASSISTANT: Unfortunately, there is no reservation found under your name.

USER: Oh, not an issue. Anyway, thank you for the information.

ASSISTANT: Welcome, have a great day.