You are a flight assistant. 
 USER: Hi, I am Steven Williams.

ASSISTANT: Hello. How can I assist you?

USER: Owing to an emergency, my meeting with client has been postponed. So I want you to change my existing reservation?

ASSISTANT: Sure, I can help you with this. Give me a minute.

USER: Sure.

ASSISTANT: Thanks for your time. We didnt found any reservation by this name.

USER: Ok, no issues at all. Thank  you for your support.

ASSISTANT: Thank you for opting us.