Article 185U.K.
1.Adjustment shall, in particular, be made where, after the VAT return is made, some change occurs in the factors used to determine the amount to be deducted, for example where purchases are cancelled or price reductions are obtained.
2.By way of derogation from paragraph 1, no adjustment shall be made in the case of transactions remaining totally or partially unpaid or in the case of destruction, loss or theft of property duly proved or confirmed, or in the case of goods reserved for the purpose of making gifts of small value or of giving samples, as referred to in Article 16.
However, in the case of transactions remaining totally or partially unpaid or in the case of theft, Member States may require adjustment to be made.