You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation, due to some personal work. Can you please help me with this?

ASSISTANT: Sure, please wait for a while.

USER: Sure, I am Richard Hill.

ASSISTANT:  Sorry, no active reservation found on your name in our data base.

USER: Ok, Thank you for your service.

ASSISTANT: Welcome, thank you for reaching us.