deed poll
noun [ S or U ] uk/ˈdiːd ˌpəʊl/ us/ˈdiːd ˌpoʊl/
（英国）单务契约，单边契约（只有一方执行的契约，常用于人名的更换）
in the UK, a type of legal document, especially one that allows someone to officially change their name
He changed his name by deed poll. 他通过单边契约改了名字。