You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Sharon Clark.

ASSISTANT: How may I help you today?

USER: Can you change my reservation as my reservation is postponed?

ASSISTANT: Sure, let me check with your reservation.

USER: Ok.

ASSISTANT: I am so sorry to inform you, but there is no active reservation found under your name in our data base.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us, have a wonderful day.