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

ASSISTANT: Hello, may I give assistance to you?

USER: I want to change my existing reservation as my source code for travel has been changed. Could you help me out in changing my reservation?

ASSISTANT: Ok, please wait let me check your reservation status.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Ok, no issues. Thank you for quick service.

ASSISTANT: Thank you for approaching us.