You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello,.

USER: I am Robert Williams.

ASSISTANT:  How may I be of your service today?

USER: I want to change my reservation, can you help me with that?

ASSISTANT:  Sure, I can help you in that.

USER: Thank you.

ASSISTANT:  Please wait, Let me check your reservation status?

USER: Ok.

ASSISTANT: Thanks for your time. Sorry. There is no active reservation on your name to change it.

USER: Ok, thanks for the information.

ASSISTANT: Thanks for approaching us.