You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: I am Brandon Allen. Due to sudden change in the dates of summit which was going to be held in the place,so I want to cancel my recent reservation, can you please help me?

ASSISTANT: Sure, I will help you with it.

USER: Ok.

ASSISTANT: There are no reservations with your details. Is there any other trip?

USER: It's ok. Thank you for your service.

ASSISTANT: Welcome.