You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Because of my ill health, I cannot make my trip to Dallas, can you favour me in cancelling my recent reservation?

ASSISTANT: Sure, I can help you with that. May I know your name to check for the previous reservation?

USER: I have reserved my ticket under the name of Patrick Hall.

ASSISTANT: Ok, please allow me a moment while I check for the previous reservation.

USER: Sure, please do it for me as it is an urgency to cancel the ticket.

ASSISTANT: Ok. Patrick, there is no reservation found under your name.

USER: It's ok, may be there is a mistake during my previous booking. Anyway, thank you for providing valuable information.

ASSISTANT: You are welcome. Thank you for contacting us.