You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Jonathan Wilson. I want to change my existing reservation because there is some changes I want to make. Can you help me?

ASSISTANT: Sure, I will help you in amend the reservation. Please wait a moment.

USER: Sure, I will wait.

ASSISTANT: Sorry Wilson, there is no reservation found on your name in our data base.

USER: Ok, no problem may be it is been changed before only. Anyways thank you for assisting me.

ASSISTANT: Thank you for reaching us.