You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: I am Robert Walker. Due to sudden changes in the dates of summit which was going to held at place.So I would like to cancel my recent reservation. Can you please help me in cancellation?

ASSISTANT: Sure, please stand by.

USER: Ok.

ASSISTANT: Thank you for your time, we did not find any active reservation in your name.

USER: Ok, no problem at all. Thank you for your great information.

ASSISTANT: Thank you for choosing us.