If there were no tickets sold then you can delete that program event:
  1. Go to Tickets
  2. Click Program Search
  3. Search and locate that program
  4. Click the event list
  5. Select the date of the canceled event 
  6. From the task menu, click Delete event
If there were tickets sold. 
  1. Go to Tickets
  2. Click Program Search
  3. Search and locate that program
  4. Click the event list
  5. Select the date of the canceled event 
  6.  From the task menu, click Edit event
  7. Change the name to have canceled in the title
  8. Go to the on sales period and select each method and press delete on your keyboard (If on a Mac press delete and Fn)
  9. You will get a pop-up window asking if you want to delete the row
  10. Click yes
  11. Click save
You may also to refund patrons who purchased tickets