You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, do you need any help from us?

USER: Owing to an emergency, my planned trip to Yosemite adventure got cancelled. So I want you to cancel my existing reservation.

ASSISTANT: Ok, could I have your name please?

USER: Sure, Barbara Brown here.

ASSISTANT: Sorry, there is no reservation with your name in our portal to make changes.

USER: Ok, no issues. Thank you for your assistance.

ASSISTANT: You are welcome.