<human>: The ranks of the Peerage in most of the United Kingdom are, in descending order of rank, duke, marquess, earl, viscount and baron; the female equivalents are duchess, marchioness, countess, viscountess and baroness respectively.  In the Scottish peerage, the lowest rank is lordship of Parliament, the male holder thereof being known as a lord of Parliament. A Scottish barony is a feudal rank, and not of the Peerage. The barony by tenure or feudal barony in England and Wales was similar to a Scottish feudal barony, in being hereditary, but is long obsolete, the last full summons of the English feudal barons to military service having occurred in 1327. The Tenures Abolition Act 1660 finally quashed any remaining doubt as to their continued status.  Peerage dignities are created by the Sovereign by either writs of summons or letters patent. Under modern constitutional conventions, no peerage dignity, with the possible exception of those given to members of the Royal Family, would be created except upon the advice of the Prime Minister.  Many peers hold more than one hereditary title; for example, the same individual may be a duke, an earl, a viscount and a baron by virtue of different peerages. If such a person is entitled to sit in the House of Lords, he still only has one vote. However, until the House of Lords Act 1999 it was possible for one of the peer's subsidiary titles to be passed to his heir before his death by means of a writ of acceleration, in which case the peer and his heir would have one vote each. Where this is not done, the heir may still use one of the father's subsidiary titles as a "courtesy title", but he is not considered a peer. CANNOTANSWER

Answer this question "how do they get two hereditary title?" by extracting the answer from the text above.
<bot>: Peerage dignities are created by the Sovereign by either writs of summons or letters patent.