You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Michelle Anderson.

ASSISTANT: How may I serve you today?

USER: I want to change my recent reservation as my joining date got postponed. Can you help me in changing?

ASSISTANT: Sure, I here to help you. Please wait for few minutes.

USER: Ok.

ASSISTANT: There is no existing reservation found on your name in our records.

USER: That's fine, thanks for the information.

ASSISTANT: Than you for approaching us.