中文摘要：

海上钻井平台的建造具有定制品之特征。为保障完工后的海上钻井平台符合其营运目的之要求，海上钻井平台建造合同的双方当事人应在合同中明确赋予买方单方变更权。买方单方变更权在法律性质上属于意定形成权，而非请求权。买方依据合同约定而享有的单方变更权不构成经济胁迫、不正当影响，也不受制于对价制度和既存义务规则，但买方单方变更权之行使应仅限于不可抗力之情形，且建造方有权要求海上钻井平台建造合同明确规定买方应对其行使单方变更权而导致的合同价格变动、交付日期迟延作出相应的变更。

英文摘要：

The construction of offshore drilling platform has the characteristics of specific products. In order to meet its opera-tional objective of offshore drilling platform completed,buyer should be entitled to unilaterally modify the contract signed. Buy-er’s right of unilateral modification should be regarded as the right of stipulated,rather than the right of claim. Buyer’s right of unilateral modification does not belong to economic duress or undue influence,and is not subject to the principle of con-sideration and pre-existing duty rule,but all of the above must be based on the case of force majeure . However,builder has the right stipulated to modify the price or delivery date which is caused by buyer’s unilateral modification.