deed poll
Concise Oxford English Dictionary © 2008 Oxford University Press:
deed poll
▶noun English Law a legal deed made and executed by one party only, especially to formalize a change of a person's name.
– origin C16: so named because the parchment was ‘polled’ or cut cleanly, not indented at the edges as in the case of a deed made by two parties.
'deed poll' also found in these Oxford entries:
