You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you today?

USER: I am Mary Martin. My sister wedding has been preponderated so, I want to change my existing reservation.

ASSISTANT: Sure, may I know your journey details?

USER: Could you please help me?

ASSISTANT: OK, please wait a moment. I will check and get back to you.

USER: OK,.

ASSISTANT: Thanks for waiting. Unfortunately there is no flight ticket reserved with your name.

USER: No Issues, Thank you for your service.

ASSISTANT: Thank you for reaching us and have a great day.