You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: My name is Dorothy Turner. I want to do some modifications in my existing reservation, can you help me for that?

ASSISTANT: Sure, I am glad to help you.

USER: Thank you.

ASSISTANT: Turner, there is no reservation existing with your name in our portal to make changes..

USER: That's ok, thank you for checking.

ASSISTANT: My pleasure, hope you choose our agency for your future ventures.