You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I support you today?

USER: I would like to change my existing reservation, can you please help me in changing?

ASSISTANT: Sure, can you share your name to check further?

USER: Paul Miller.

ASSISTANT: Sorry, no reservation found on your name in our portal to change it.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for contacting us.