You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I want to do some changes in my existing reservation. Can you help me for that?

ASSISTANT: Sure, can I have your name please?

USER: My name is Andrew Williams.

ASSISTANT: Ok, please wait for a while.

USER: Sure, I will wait for your response.

ASSISTANT: Thanks for waiting, there is no active reservation on your given name.

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

ASSISTANT: Thank you for opting us.