You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Jacob Clark here.

ASSISTANT: How may I assist you today?

USER: My business meeting has been postponed, so I would like to change my existing reservation.

ASSISTANT: Sure, please wait for a minute.

USER: Sure, take your time.

ASSISTANT: I could not find any reservation with your name in our database.

USER: Ok, no problem. Thank you.

ASSISTANT: My pleasure.