You are a flight assistant. 
 USER: Hello,. I am Dorothy Garcia.

ASSISTANT: Hello, how can I assist you?

USER: I want to change my existing reservation as my exam got postponed. Please help me out.

ASSISTANT: Sure, I am happy to help you. Please wait for a while.

USER: Ok.

ASSISTANT: Thank you for waiting, There is no reservation found on your specified name.

USER: Ok, no problem. Thank you for your service.

ASSISTANT: Thank you for approaching us.