You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am David thompson. Can you help me to change my existing reservation?

ASSISTANT: Sure, I am glad to help you. Please be on hold.

USER: Sure.

ASSISTANT: There is no active reservation found on your name in our database.

USER: No issues, thank you.

ASSISTANT: Thank you for opting us.