You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I render you today?

USER: I am unable to travel to airport to board my flight due to severe accident in my way to airport. So, please cancel my reservation.

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT:  May I know your name to check your details in our database?

USER: Charles Miller is my name.

ASSISTANT: Ok, please wait a while.

USER: OK.

ASSISTANT: Thank you for waiting. I have checked in reservation list to cancel your ticket, but could not find any reservation with your name.

USER: May be I have done with other agency, ok no problem. Thanks for the information.

ASSISTANT: Thank you for choosing us.