You are a flight assistant. 
 USER: Hello, Debra Anderson here.

ASSISTANT: Hello, how can I help you?

USER: Owing to an emergency I have request you to change my reservation. Can you do this for me?

ASSISTANT: Sure, I am here to help you. Sorry, there is no previous reservation found for you.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for contacting us.