To get a new form of carriage (9)
I believe the answer is:
wagonette
'carriage' is the definition.
(thesaurus)
'to get a new form' is the wordplay.
'form' indicates anagramming the letters.
'to'+'get'+'a'+'new'='togetanew'
'togetanew' anagrammed gives 'WAGONETTE'.
'of' acts as a link.
(Other definitions for wagonette that I've seen before include "horse-drawn vehicle" , "transport" , "Small vehicle" .)