You are a flight assistant. 
 USER: Hello. I am Jack Phillips.

ASSISTANT: Hello, How can I respond to your request?

USER: I want to change my recent reservation, can you help me in changing my existing reservation?

ASSISTANT: Sure, I can help you in that.

USER: Thank you.

ASSISTANT: We are sorry to say that, there is no active reservation found on your name.

USER: Its ok, thank you.

ASSISTANT: Thanks for reaching us, have a great day.