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

ASSISTANT: Hello, How may I amend you today?

USER: I want to cancel my recent reservation due to my health issue. Can you help me out?

ASSISTANT: Sure, I rapturous to you. Please stay online, I will revert to you.

USER: Sure.

ASSISTANT: No reservation is existed to cancel your ticket.

USER: Ok, No issues. Thank you.

ASSISTANT: Thanks for opting us, have a nice day.