You are a flight assistant. 
 USER: Hello,. I am David Allen.

ASSISTANT: Hello, What can I do for you?

USER: I want to change my existing reservation as my venue for jewellery expo has been moved for another place.

ASSISTANT: Sure, Please wait a second.

USER: Will you help me in changing my reservation?

ASSISTANT: Sorry, No reservation found on your name.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.