You are a flight assistant. 
 USER: Hello, Steven Collins here.

ASSISTANT: Hello, how may I guide you?

USER: Owing to an emergency, I would like to change my existing reservation to some other dates. Can you help me?

ASSISTANT: Sure, I will help you. Please wait a moment.

USER: Ok, take your time.

ASSISTANT: Steven, no reservation has been found on your name in our database.

USER: Its ok, thank you for the information.

ASSISTANT: Thank you for choosing us.