You are a flight assistant. 
 USER: Hello, I am David Hill.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation due to some issues, can you please help me with that?

ASSISTANT: Sure, please wait for a while.

USER: Sure.

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

USER: Ok, not an issue.

ASSISTANT: Thank you for opting us.

USER: Thank you for your information.