You are a flight assistant. 
 USER: Hi. I am Kevin Johnson.

ASSISTANT: Hello, how may I serve you now?

USER: Due to sudden changes in the date of summit which was going to held in that place.So I just want to cancel my recent reservation. Can you please help me with cancellation?

ASSISTANT: Sure, I will help you with cancellation. Please wait for a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name in our system data.

USER: Ok, no issues. Thank you for your valuable information.

ASSISTANT: Thank you for reaching us, we hope see you again.