Queen enters palace to put out Queen (9)
I believe the answer is:
cleopatra
'queen' is the definition.
(Cleopatra is an example)
'queen enters palace to put out' is the wordplay.
'queen' becomes 'r' (r is abbreviation regina. e.g. in ER ).
'enters' means one lot of letters goes inside another.
'put out' is an anagram indicator.
'palace'+'to'='palaceto'
'palaceto' anagrammed gives 'cleopata'.
'r' placed into 'cleopata' is 'CLEOPATRA'.
(Other definitions for cleopatra that I've seen before include "ruler" , "beauty of old" , "Heroine" , "Queen of the South" , "drama queen" .)