You are a flight assistant. 
 USER: Hello, I am Debra Mitchell.

ASSISTANT: Hello, Debra Mitchell. How can I assist you today?

USER: Owing an emergence, I want to change my existing reservation.Can you help me with it?

ASSISTANT: Sure, please wait a moment I will and revert to you.

USER: Ok.

ASSISTANT: Sorry to say no reservation found on your given name.

USER: Ok, no issues.

ASSISTANT: Thank you for opting us. Have a nice day.

USER: Thanks for the service.