Article 86 CISG
(1) If the buyer has received the goods and intends to exercise any right under the contract or this Convention to reject them, he must take such steps to preserve them as are reasonable in the circumstances. He is entitled to retain them until he has been reimbursed his reasonable expenses by the seller.
(2) If goods dispatched to the buyer have been placed at his disposal at their destination and he exercises the right to reject them, he must take possession of them on behalf of the seller, provided that this can be done without payment of the price and without unreasonable inconvenience or unreasonable expense. This provision does not apply if the seller or a person authorized to take charge of the goods on his behalf is present at the destination. If the buyer takes possession of the goods under this paragraph, his rights and obligations are governed by the preceding paragraph.