You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you today?

USER: Can you change my existing reservation?

ASSISTANT: Sure, Kindly share your name.

USER: Sure, My name is Richard Roberts.

ASSISTANT: Sorry to inform you, there is no reservation found with your name.

USER: Ok, No issues. Thank you.

ASSISTANT: Thank you for choosing us.