You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am William Baker. I want to change my recent reservation. Can you help me out?

ASSISTANT: How can I aid you today? Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Sorry to intimate, no reservation is found with your criteria.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: Thank you for choosing us.