You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,.

USER: I am Jack Roberts.

ASSISTANT: How can I assist you today?

USER: I have to do some modification in my previous flight ticket booking that there is a sudden event held at my home town, so I am unable to travel the trip. can you please help me out with changing of my reservation?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Give me a moment to check with your reservation.

USER: Sure, take your time.

ASSISTANT: Thanks for waiting. Sorry Roberts, there is no active reservation found on your name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for opting us.