You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Thomas Brown here.

ASSISTANT: How can I assist you?

USER: Due to sudden change in my travel location, I would like to change my reservation, can you please help me out with changing of my reservation?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure, take your time.

ASSISTANT: I am sorry to say that there is no reservation found.

USER: Oh! I think the ticket was not booked properly while I am booking. Anyway, thank you for the information.

ASSISTANT: Thank you for contacting us, have a great day.

USER: Welcome.