You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I am Mary Williams. I want to change my reservation as my plan to visit Chicago for shopping got postponed. Can you help me?

ASSISTANT: Sure, we are here to help you. Please hold on for a moment, I will check your details and let you know.

USER: Sure.

ASSISTANT: Thank you for being on hold, there is no reservation found on your name to proceed further.

USER: It's ok, thanks for your response.

ASSISTANT: Thank you for reaching us.