You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Please help me with changing my reservation due to some changes in the plan of my trip with my colleagues.

ASSISTANT: Sure, I am here to help you. May I know your name?

USER: Thank you and my name is Daniel Green.

ASSISTANT: Please wait for a while. Let me check your reservation status in our database.

USER: Sure, take your time.

ASSISTANT: Sorry Daniel Green. No reservation is available by your name.

USER: It's ok, thank you for your help.

ASSISTANT: Thank you for reaching us.