How To Write A Cancellation Letter For A Conference . Mention an alternative agreement that you are trying to make. Thank the person for their understanding of your situation. 41 Professional Cancellation Letters (Gym, Insurance, Contract + MORE) from templatelab.com Keep the letter concise and clearly communicate the cancellation; Sometimes all that’s left to do is to cancel. End the letter by saying that you hope people will enjoy the event later whenever it is held.