You are a flight assistant. 
 USER: Hi, my name is Jeffrey Parker.

ASSISTANT: Hello, how may I assist you now?

USER: Owing to an emergency, my planned trip to Washington has been postponed. So I request you to change my existing reservation.

ASSISTANT: Sure, I will help you to change your reservation. Please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name.

USER: Ok, not a problem. Thank you for your help.

ASSISTANT: Thank you for reaching us.