You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Helen Roberts.

ASSISTANT: How may I assist you Helen Roberts?

USER: Due to health problems I need to cancel my recent reservation, Can you help me for cancel reservation please?

ASSISTANT: Sure, wait a moment. I will check and cancel.

USER: Sure.

ASSISTANT: Sorry, we did not find any reservation on your name to cancel.

USER: Ok, no problem. Thanks for your good response.

ASSISTANT: Thanks for contacting us.