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。