1. Edit accommodation.
  2. Choose the Price list tab.
  3. Choose the Discounts 2nd level tab.
  4. Find a discount you wish to delete and click the Delete icon.
  5. Click OK to save changes.

HINT: If you want reservations to have new price without discount, you have to edit reservation and recalculate the price. You also have to recreate documents with new price. More about this option find in chapter Change reservation price after price list change.