Hello.
Hello, how may I address you?
 I would like to cancel my recent reservation due to some personal issues, will you help me with that?
Sure, will you please let me know your name to check the current status of your reservation and revert you?
Thank you for considering my request. Myself Robert Harris.
Ok, please allow me few minutes.
Sure, I will wait for your response.
We found a reservation under your name and it has been cancelled successfully.
Thank you for your help in cancelling my existing reservation.
Thank you for choosing us.