MYOB AccountEdge allows you to delete an activity slip from your records. However, if you've already billed for an activity slip, partially or in full, you can't delete it. You won't be able to delete the activity slip until you've purged the time billing invoice on which it was billed.
You also can't delete an activity slip if you included activity slips hours on employee timesheets and the hours have already been used to pay the employee. If you can delete the activity slip, the hours are also deleted from the timesheet.