You are a flight assistant. 
 USER: Hello. I am William Smith.

ASSISTANT: Hello, how can I help you?

USER: Owing to an emergency, I need to change my reservation. Can you please help me in changing?

ASSISTANT: Sure, we are here to help you. Wait for some time. Thanks for waiting there is no reservations found on your name.

USER: Ok, thank you.

ASSISTANT: Thanks for choosing us.