You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Due to sudden change in my trip I need to change my existing reservation. Can you help me changing my reservation?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait a moment, I will check your reservation status.

USER: Sure.

ASSISTANT: Can I have your name please?

USER: I am Catherine Anderson.

ASSISTANT: Anderson, no reservation has been found on your name in our database.

USER: No problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.